COLORED PHOTOVOLTAIC ROOF TILES.

Abstract

One modality may provide a photovoltaic tile module; the photovoltaic tile module may include a front encapsulating layer and a rear encapsulating layer where both the front and rear encapsulating layers include different pigments; the front encapsulating layer may include a small amount of pigment that absorbs and scatters particular frequencies of visible light to give the photovoltaic tile a desired color; the small amount of pigment does not absorb or scatter a significant amount of infrared light; two or more photovoltaic tiles may be combined to form a photovoltaic module; the two or more photovoltaic tiles may have different concentrations of pigment in the front encapsulating layer to give the photovoltaic module a small amount of color variation.

Description

This application claims priority to U.S. Provisional Patent Application 63 / 115,481, COLORED PHOTOVOLTAIC ROOF TILES, filed on November 18, 2020. FIELD OF INVENTION This description generally relates to solar roof tiles. More specifically, this description describes infusing one or more layers of encapsulant surrounding the solar cells of a photovoltaic roof tile with pigment to alter the tile's cosmetic appearance. BACKGROUND OF THE INVENTION In residential and commercial solar energy installations, a building's roof is typically fitted with photovoltaic (PV) modules, also called PVs or solar panels, which can include a two-dimensional array (e.g., 6 x 12) of solar cells. A PV tile (or solar tile) is a specific type of PV module that provides weather protection for the house and an aesthetically pleasing appearance, while also functioning as a PV module to convert solar energy into electricity. A PV tile can be molded similarly to a conventional roof tile and may include one or more solar cells encapsulated between a front and back cover, but it typically encloses fewer solar cells than a conventional solar panel. The front and back covers can be reinforced with glass or another material that protects the PV cells from the elements. Note that a typical roof tile might measure 38.1 cm (15 in) x 20.32 cm (8 in) = 120 in² = 774 cm², and a typical solar cell might measure 15.24 cm (6 in) x 6 in = 36 in² = 232 cm². Similar to a conventional PV panel, a PV roof tile may include an encapsulation layer, such as an organic polymer. A lamination process can seal the solar cells between the front and back covers. Unfortunately, PV roof tiles are generally not available in the same number of colors as a conventional roof tile. For these reasons, methods and devices for offering PV roof tiles in a variety of colors are desirable. b / Qcnn / cznz / B / vi BRIEF DESCRIPTION OF THE INVENTION One modality may provide a photovoltaic tile module. The photovoltaic tile module may include a plurality of photovoltaic tiles coupled mechanically and electrically to each other. A respective photovoltaic tile module is described and may include a photovoltaic tile comprising a front glass cover, a front encapsulating layer doped with a second pigment different from the first pigment corresponding to a color of the plurality of solar cells; and a plurality of solar cells placed between the front and rear encapsulating layers. A photovoltaic tile is described and may include a front glass cover; a front encapsulating layer doped with a first pigment; a plurality of solar cells; and a rear encapsulating layer doped with a second pigment different from the first pigment that corresponds to a color of the plurality of solar cells. In some configurations, the front encapsulating layer of a first photovoltaic tile has five to ten percent more of the first pigment than the front encapsulating layer of a second photovoltaic tile adjacent to the first. A solar cell, or solar cell, is a photovoltaic structure capable of converting light into electricity. A cell can be any size and any shape and can be created from a variety of materials. For example, a solar cell can be a photovoltaic 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 the photovoltaic structure) or a combination thereof. A solar cell strip, photovoltaic strip, smaller cell, or strip is a segment of a photovoltaic structure, such as a solar cell. A photovoltaic structure can be divided into multiple strips. A strip can be any shape and size. The width and length of a strip can be the same or different. Strips can be formed by further dividing a previously divided strip. Finger lines, finger electrodes, and fingers refer to elongated, electrically conductive (e.g., metallic) electrodes of a photovoltaic structure for collecting carriers A busbar, bus line, or bus electrode refers to elongated, electrically conductive (e.g., metallic) electrodes of a photovoltaic structure used to aggregate current collected by two or more finger lines. A busbar is usually wider than a finger line and can be deposited or otherwise positioned anywhere on or within the photovoltaic structure. A single photovoltaic structure may have one or more busbars. A photovoltaic structure can refer to a solar cell, a segment, or a strip of solar cells. A photovoltaic structure is not limited to a device manufactured by a particular method. For example, a photovoltaic 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 of these. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 shows an exemplary configuration of PV tiles on a house. FIG. 2 shows a front perspective view of an exemplary photovoltaic tile, in accordance with one modality. FIG. 3A shows an exemplary configuration of a multi-tile module, in accordance with one modality. FIG. 3B shows a cross-section of a module of multiple exemplary tiles, in accordance with a modality. FIG. 4A illustrates a serial connection between three adjacent photovoltaic strips, in accordance with one modality. FIG. 4B illustrates a side view of the cascading strip chain, in accordance with one modality. FIG. 4C illustrates an exemplary solar tile, in accordance with one modality. FIG. 5A shows a top view of a module of multiple exemplary tiles, in accordance with a modality. FIG. 5B shows a top view of another exemplary solar tile, in accordance with one modality. FIG. 6 shows a partial view of a yew tree that has several solar tiles and passive tiles. FIG. 7A shows an exploded view of an exemplary photovoltaic tile, in accordance with one modality. FIGS. 7B to 7D show how a concentration of pigment within a front encapsulating layer can allow variation in the cosmetic appearance of photovoltaic tiles. FIGS. 8A to 8C show side views of exemplary photovoltaic tiles, in accordance with some modalities. FIG. 9 shows a flow diagram illustrating a manufacturing process for a photovoltaic tile. b / Qcnn / eznz / e / Yi FIG. 10 shows an image of encapsulating material mixed with the first and second pigments. FIG. 11 shows an image of a photovoltaic tile module incorporating a front encapsulant layer doped with a first pigment and a second pigment. DETAILED DESCRIPTION OF THE INVENTION The following description is presented to enable any person skilled in the art to perform and use the modalities, and is provided within the context of a particular application and its requirements. Several modifications to the described modalities will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other modalities and applications without deviating from the spirit and scope of this description. Thus, the system described is not limited to the modalities shown, but rather is consistent with the broader scope inherent in the principles and characteristics described herein. Generalities The embodiments of the invention solve at least the technical problem of improving the aesthetics of solar roof tiles at a low cost. A solar roof tile (or PV tile) may include several solar cells sandwiched between a front glass cover and a back cover. Due to manufacturing imperfections, the solar cells, and therefore the PV tiles, may have inherent color variations. In addition, PV tiles may also have different color appearances under different lighting and / or at different viewing angles. To mitigate color contrast, either within a PV tile or between PV tiles and non-PV roof tiles, a robust color management scheme is adopted during tile manufacturing in some embodiments. First, to reduce color contrast within a PV tile, the PV tile may encapsulate monocrystalline or polycrystalline silicon-based photovoltaic structures.By controlling the size and pattern of the surface texture of monocrystalline or polycrystalline silicon-based photovoltaic structures, one can reduce anisotropic optics, sometimes described as the glare of the photovoltaic structures. While keeping the front surface of the tile transparent, the back surface can be coated with a layer of paint that matches the color of the textured surface of the photovoltaic structures to reduce color contrast within the PV tile. A similar paint layer can also be applied to the back surface of non-PV tiles. As a result, the color appearance of the PV and non-PV tiles can be quite similar. Alternatively, an encapsulant layer placed behind the photovoltaic structures can be colored with pigment to match the color of the photovoltaic structures, thus reducing color contrast around the perimeters of the PV tile. b / acnn / eznz / B / Yi Furthermore, when the PV tiles are assembled, the integrated photovoltaic structures are fed into the production line following a predetermined color pattern so that most of the PV tiles contain solar cells of a similar color and PV tiles of different colors are uniformly or randomly mixed to prevent clumping of colors on a roof. In some applications, one can also create PV shingles as well as non-PV shingles that have significantly different surface colors by selectively treating the encapsulating face layer with pigment. There are different ways to treat the face encapsulating face layer. By varying the amount of pigment within the face encapsulating face layer in a series of adjacent shingles, a roof top can have a non-uniform appearance. In some versions, a rear encapsulating layer can be treated with pigment that matches the color of the photovoltaic structures. In this configuration, the overall color of a given photovoltaic tile can be determined by the colors of both the front and rear encapsulating layers. A solar cell, or simply cell, is a photovoltaic structure capable of converting light into electricity. A cell can be any size and shape and can be made from a variety of materials. For example, a solar cell can be a photovoltaic structure fabricated on a silicon wafer, one or more thin films on a substrate material (such as glass, plastic, or any other material capable of supporting the photovoltaic structure), or a combination of these. A solar cell strip, photovoltaic strip, smaller cell, or strip is a segment of a photovoltaic structure, such as a solar cell. A photovoltaic structure can be divided into multiple strips. A strip can be any shape and size. The width and length of a strip can be the same or different. Strips can be formed by further dividing a previously divided strip. Finger lines, finger electrodes, and fingers refer to elongated, electrically conductive (e.g., metallic) electrodes of a photovoltaic structure for collecting carriers A busbar, bus line, or bus electrode refers to elongated, electrically conductive (e.g., metallic) electrodes on a photovoltaic array used to aggregate current collected by two or more finger lines. A busbar is usually wider than a finger line and can be deposited or otherwise positioned anywhere on or within the photovoltaic array. A single photovoltaic array may have one or more busbars. A photovoltaic structure can refer to a solar cell, a segment, or a strip of solar cells. A photovoltaic structure is not limited to a device manufactured by a particular method. For example, a photovoltaic 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 of these. PV Tiles and Multi-Tile Modules A PV tile (or solar tile) is a type of molded PV module similar to a roof tile and typically enclosing fewer solar cells than a conventional solar panel. Note that such PV tiles can function as both PV cells and roof tiles simultaneously. In some configurations, the system described herein can be applied to PV tiles and / or other types of PV modules. Figure 1 shows an exemplary configuration of PV tiles on a house. PV 100 tiles can be installed on a house similarly to conventional tiles or shingles. In particular, a PV tile can be laid with other tiles in such a way as to prevent water from entering the building. A PV tile can enclose multiple solar cells or PV structures, and a respective PV structure can include one or more electrodes, such as bus bars and finger lines. The PV structures within a PV tile can be coupled to each other electrically and, optionally, mechanically. For example, multiple PV structures can be electrically coupled together by a metal tab, via their respective bus bars, to create serial or parallel connections. In addition, electrical connections can be created between two adjacent tiles so that several PV tiles can jointly provide electrical power. Cosmetic features of PV tiles can allow them to blend in and look similar to non-PV tiles. In some configurations, the cosmetic features can be designed to operate ideally when viewed from a 10° angle. Figure 2 shows a perspective view of an exemplary photovoltaic tile, according to one embodiment. Solar cells 204 and 206 can be hermetically sealed between the upper glass cover 202 and the reinforcing sheet 208, which together protect the solar cells from various climatic elements. In the example shown in Figure 2, metal tabulation strips 212 can be in contact with the electrodes on the front side of solar cell 204 and extend beyond the left side of the glass 202, thus serving as contact electrodes for a first polarity of the PV tile. Tabulation strips 212 can also be in contact with the rear of solar cell 206, creating a serial connection between solar cell 204 and solar cell 206.On the other hand, two tabulation strips 214 may be in contact with the electrodes on the front side of the solar cell 206 and extend beyond the right side of the glass cover 202, serving as contact electrodes for a second polarity of the PV tile. In some embodiments, the reinforcing sheet 208 may be a standard reinforcing sheet formed from one or more polymer layers such as, for example, fluoropolymers or combinations of PET b / Qcnn / cznz / e / Yi and EVA layers. Alternatively, the reinforcing sheet 208 may take the form of a rear glass cover. In some embodiments, the solar cell array 204 and 206 may be encapsulated between the upper glass cover 202 and the rear cover 208. An upper encapsulating layer, which may be polymer-based, may be used to seal the upper glass cover 202 to the solar cell array 204 / 206. Specifically, the upper encapsulating layer may include polyvinyl butyral (PVB), thermoplastic polyolefin (TPO), ethylene vinyl acetate (EVA), or N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,R-diphenyl-4,4'-diamine (TPD). Similarly, a lower encapsulating layer, which may be based on a similar material, can be used to seal the solar cell array to the back cover 208. A PV tile may also contain other optional layers such as an optical fiber or coating layer or a nanoparticle layer to provide the desired color appearances. In the example in FIG.2, the module or tile 300 may also contain an optical filter layer between the solar cell array and the front glass cover 202. To facilitate more scalable production and simpler installation, multiple photovoltaic tiles can be manufactured together, with the tiles linked in a rigid or semi-rigid manner. Figure 3A shows an exemplary configuration of a multi-tile module, according to one modality. In this example, three PV tiles 302, 304, and 306 can be manufactured by establishing semi-rigid couplings 322 and 324 between adjacent tiles. Prefabricating multiple tiles in a rigid or semi-rigid multi-tile module can significantly reduce the complexity of roof installation because the tiles within the module are connected with tabulation strips. Note that the number of tiles included in each multi-tile module can be more or less than shown in Figure 3A. Figure 3B shows a cross-section of an exemplary multi-tile module, according to one embodiment. In this example, the multi-tile module 350 can include photovoltaic tiles 354, 356, and 358. These tiles can share common reinforcing sheets 352 and have three individual glass covers 355, 357, and 359, respectively. Each tile can encapsulate two solar cells. For example, tile 354 can include solar cells 360 and 362 encapsulated between reinforcing sheets 352 and glass cover 355. Tabulation strips can be used to provide electrical coupling within each tile and between adjacent tiles. For example, tabulation strip 366 can couple the front electrode of solar cell 360 to the rear electrode of solar cell 362, creating a serial connection between these two cells.Similarly, tabulation strip 368 can couple the front electrode of cell 362 to the rear electrode of cell 364, creating a serial connection between tile 354 and tile 356. b / acnn / eznz / B / Yi The spaces 322 and 324 between adjacent PV tiles can be filled with encapsulant, protecting the tabulation strips that interconnect the two adjacent tiles from the elements. For example, encapsulant 370 fills the space between tiles 354 and 356, protecting tabulation strip 368 from the elements. Furthermore, the three glass covers, reinforcing sheet 352, and encapsulant together form a semi-rigid structure for the multi-tile module. This semi-rigid structure facilitates easier installation while providing a degree of flexibility between the tiles. In addition to the examples shown in Figures 3A and 3B, a PV tile can incorporate various photovoltaic structures. For example, to reduce internal resistance, each square solar cell shown in Figure 3A can be divided into multiples (e.g., three) of smaller strips (e.g., three), each having side bus bars of opposite polarities on its two opposite sides. These side bus bars can be cascaded to form a serially connected string. Figure 4A illustrates a serial connection between three adjacent cascaded photovoltaic strips, according to one modality. In Figure 4A, strips 502, 504, and 506 are stacked such that strip 504 partially overlaps the adjacent strip 506 to its right and overlaps strip 502 to its left. The resulting string of strips forms a cascade pattern similar to roof tiles. Strips 502 and 504 are electrically coupled in series via side bus bar 508 on the upper surface of strip 502 and side bus bar 510 on the lower surface of strip 504. Strips 502 and 504 can be arranged such that the lower side bus bar 510 is above and in direct contact with the upper side bus bar 508. The coupling between strips 504 and 506 can be similar. Figure 4B illustrates a side view of the cascaded strip string, according to one modality. In the example shown in Figures 4A and 4B, the strips can be square or pseudo-square solar cell segments of 15.24 centimeters (six inches), with each strip having a dimension of approximately 5.08 centimeters (2 inches) by 15.24 centimeters (six inches). To reduce shading, the overlap between adjacent strips should be kept as small as possible. Therefore, in the example shown in Figures 4A and 4B, single bus bars (both on the top and bottom surfaces) can be placed on or near each side of the strip. The same cascade pattern can be extended along multiple strips to form a serially connected string, and multiple strings can be coupled in series or in parallel. Figure 4C illustrates an exemplary solar tile, according to one embodiment. A solar tile 412 includes the upper glass cover 414 and solar cells 516 and 518. The lower cover (e.g., reinforcing sheet) of solar tile 412 is not visible in Figure 4C. Solar cells 416 and 418 can be conventional square or half-square solar cells, such as 15.24-centimeter (six-inch) solar cells. In some embodiments, the solar cells b / acnn / eznz / B / Yi 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 the sides, similar to those shown in Figures 4A to 4B. For simplicity of illustration, the electrode grids, including finger lines and side bus bars, of the strips are not shown in Figure 4C. In addition to the examples shown in Figure 4C, a solar tile can contain fewer or more cascade strips, which can be of various shapes and sizes. In some configurations, multiple solar tiles, each encapsulating a cascade string, can be assembled to form a multi-tile module. Internal tile electrical couplings have been achieved by overlapping the corresponding side 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-connecting strips have been used to facilitate inter-tile coupling. However, strain-relief connectors can be expensive, and arranging the bus-connecting strips after exposing the cascaded strips can be complex.To facilitate high-volume production of solar tiles, in some designs, metal strips can be pre-placed on the back covers of the solar tiles, forming a closed-loop system similar to the metal traces on a printed circuit board (PCB). More specifically, the integrated circuit system can be configured to facilitate electrical coupling between multiple solar tiles within a multi-tile module. Furthermore, to facilitate electrical coupling between the integrated circuit system and a side bus bar located on the front surface of a cascade, in some embodiments, a silicon-based bridging electrode can be attached to the cascade. The silicon-based bridging electrode may include a metallic layer covering its entire rear surface and, optionally, a rear side bus bar. By overlapping its side (e.g., the rear side bus bar) with the front side bus bar of the cascade, the silicon-based bridging electrode can itself become an electrode for the cascade, converting the forward-facing electrode of the cascade into an electrode accessible from the rear of the cascade. Figure 5A shows a top view of an exemplary multi-tile module, in accordance with one modality. The 600 multi-tile module may include PV tiles 502, 504, and 506 arranged side by side. Each PV tile may include six cascading strips encapsulated between the front and back covers, meaning that the bus bars on opposite sides of the cascading strip chain have opposite polarities. For example, if the leftmost bus bar on the strips in PV tiles 502 has a positive polarity, then the rightmost bus bar b / cicnn / eznz / B / Yi will have a negative polarity. Serial connections can be established between tiles by electrically coupling bus bars that have opposite polarities, while parallel connections can be established between tiles by electrically coupling bus bars that have the same polarity. In the example shown in FIG. 5A, the PV tiles are arranged so that their sun-facing sides have the same electrical polarity. As a result, the bus bars on the same side with the same polarity will be on the same right or left side. For example, the rightmost bus bar on all the PV tiles might have a positive polarity, and the leftmost bus bar on all the PV tiles might have a negative polarity, or vice versa. In FIG. 6, the left-side bus bars on all the strips have a positive polarity (indicated by the + sign) and are located on the sun-facing (or front) surface of the strips, while the right-side bus bars on all the strips have a negative polarity (indicated by the - sign) and are located on the back surface.Depending on the design of the solar cell layer structure, the polarity and location of the side bus bars may be different from those shown in FIG. 5A. A parallel connection between tiles can be formed by electrically coupling all the leftmost bus bars together via metal tab 510 and all the rightmost bus bars together via metal tab 512. Metal tabs 510 and 512 are also known as connecting buses and are typically used for interconnecting individual solar cells or strings. A metal tab can be stamped, cut, or otherwise formed from conductive material such as copper. Copper is a highly conductive and relatively inexpensive connecting 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 configurations, heat-treated alloys with superelastic properties can be used for all or part of the metal tab.Suitable alloys may include, for example, copper-zinc-aluminum (CuZnAl), copper-aluminum-nickel (CuAINi), or copper-aluminum-beryllium (CuAIBe). Furthermore, the metal tab material described herein may be manipulated, in whole or in part, to alter its mechanical properties. For example, all or part of the metal tabs 510 and 512 may be forged (e.g., to increase strength), annealed (e.g., to increase ductility), and / or hardened (e.g., to increase surface hardness). The coupling between a metal tab and a bus bar can be facilitated by a specially designed voltage-reducing connector. In FIG. 5A, voltage-reducing connector 516 can be used to couple bus bar 514 and metal tab 510. Such voltage-reducing connectors are necessary due to the mismatch of the coefficients of thermal expansion between metal (e.g., Cu) and silicon. As shown in FIG. 5A, metal tabs (e.g., tabs 510 and 512) can cross paths with voltage-reducing connectors of opposite polarities. To prevent short-circuiting of the photovoltaic strips, portions of the metal tabs and / or voltage-reducing connectors can be coated with an insulating film or wrapped with a sheet of insulating material. In some embodiments, instead of coupling the tiles in parallel within a tile module using stamped metal tabs and strain relief connectors as shown in FIG. 5A, one can also form serial coupling between the tiles. FIG. 5B shows the top view of an exemplary multi-tile module, according to one embodiment. Module 540 may include solar tiles 542, 544, and 546. Each tile may include several cascade solar cell strips (for example, six) arranged in a manner shown in FIGS. 4A and 4B. In addition, the metal tabs may be used to interconnect photovoltaic strips enclosed in adjacent tiles. For example, metal tab 648 may connect the front of strip 632 to the back of strip 630, creating serial coupling between strips 630 and 632. Although the example in FIG.Figure 5B shows three metal tabs interconnecting the photovoltaic strips; other numbers of metal tabs can also be used. Furthermore, each solar tile can contain fewer or more cascade strips, which can be of various shapes and sizes. For simplicity of illustration, FIGS. 5A and 5B do not show inter-tile spacers that provide support and facilitate mechanical and electrical coupling between adjacent tiles. Detailed descriptions of such inter-tile spacers can be found in U.S. Patent Publication US20190260328A1, entitled INTER-TILE SUPPORT FOR SOLAR ROOF TILES, the description of which is incorporated herein by reference in its entirety. Color Matching in Solar Tiles As shown in Figures 4C, 5A, and 5B, photovoltaic arrays and external electrodes encapsulated between the front and back covers can appear different from the background when viewed from the side of the transparent, uncolored front cover. More specifically, silicon-based photovoltaic arrays often appear to have a blue / purple tint. Although applying color to the back cover can improve color matching between the photovoltaic arrays and the background, it cannot resolve the angle-dependent problem of color. In other words, the photovoltaic arrays may appear to have different colors at different viewing angles, making color matching difficult. Furthermore, in addition to solar tiles, a roof may sometimes include a number of passive or dead tiles—that is, tiles that do not have integrated solar cells.These passive roof tiles may simply consist of the b / Qcnn / eznz / e / Yi front and back covers and an encapsulant sandwiched between them. The difference in appearance between salt tiles and passive roof tiles often results in a less aesthetically pleasing result. Figure 6 shows a partial view of a tile that includes several solar and passive tiles. In Figure 6, the 600 roof may include several tiles arranged in such a way that the lower sides of the tiles in an upper row overlap the upper sides of the tiles in a lower row, thus preventing water leakage. Furthermore, the tiles are offset so that the space between adjacent tiles in one row aligns somewhat with the center of a tile in a different row. In the example shown in Figure 6, tiles 602, 604, 606, and 608 are solar tiles, which may include photovoltaic structures encapsulated between the front and back covers, and tiles 610 and 612 are passive tiles. As can be seen from the drawings, the color contrast between the back covers and the photovoltaic structures can create a picture-frame appearance for the solar tiles.In fact, photovoltaic structures often appear to be floating above the colored back tiles. Ideally, solar tiles 602 to 608 should have a similar appearance to passive tiles 610 and 612. Spacers 614 can fill the spaces between adjacent tiles and prevent water from passing between photovoltaic tiles 602 to 608. In some configurations, spacers 614 can include electrical conductors that allow the passage of electricity and / or signals between adjacent photovoltaic tiles. In some configurations, spacers 614 can define channels through which wires or similar conductors can carry electricity and / or signals between adjacent photovoltaic tiles. Figure 7A shows an exploded view of an exemplary photovoltaic tile 700. Photovoltaic tiles 700 include a front glass cover 702. The front glass cover 702 may have a textured and / or rearward-facing front surface to help diffuse light entering and exiting the photovoltaic tile 700. The photovoltaic tile 700 also includes the front encapsulant layer 704 and the rear encapsulant layer 706. The encapsulant layers may be formed from electrically transparent, optically insulating materials such as polyvinyl butyral (PVB), thermoplastic polyolefin (TPO), ethylene vinyl acetate (EVA), and N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1,-diphenyl-4,4'-diamine (TPD).In some configurations, a small amount of inorganic pigment can be incorporated into one or both of the 704 and 706 encapsulant layers to give the 700 photovoltaic tile a desired appearance without substantially impeding the flow of solar energy through the front 704 encapsulant layer. The pigment typically creates less than 1% of the 704 encapsulant layer. To create the light-opaque 706 encapsulant layer, it should generally be composed of two to five percent pigment. The inorganic pigment should be substantially transparent to infrared light, resulting in the incorporation of the pigment causing no more than a 10% reduction in the total amount of solar energy collected by the 700 photovoltaic tile.In some configurations, a 20% reduction may result when brighter-colored PV tiles are desired, as the amount and / or type of pigment needed to achieve a brighter color can interfere more with solar energy input. For example, pigments based on titanium oxide (e.g., TiO2) or iron oxide (e.g., FeCh or FeOn) can be impregnated within the front encapsulating layer to give the photovoltaic tiles gray and brown hues, respectively. Additional pigment types include chromium oxide (e.g., CrCh) for green, cadmium for yellow, orange, or red, and cobalt oxides for blue. Higher concentrations, for example, an iron oxide-based pigment, could also be used to achieve a red or orange color.Although inorganic pigments are generally considered desirable for their stability, organic pigments can also be used in certain configurations since they can be more transparent to infrared light than inorganic pigments. The amount of pigment impregnated in the material used to form the 704 front encapsulant layer can vary based on the type of pigment used and the thickness of the front encapsulant layer. For example, higher pigment concentrations could be used with relatively thinner front encapsulant layers. In some configurations, a pigment concentration can make up as little as 0.5% of the material that forms the 704 front encapsulant layer. A front encapsulant layer thickness with this pigment concentration can range from 350 to 600 microns. In some configurations, a thickness of 450 to 500 microns may be desirable. Maintaining a consistent 704 front encapsulant layer thickness is desirable because variations in thickness can result in undesirable variations in color and overall thickness of the photovoltaic tiles.Furthermore, although a specific example of a non-organic pigment is provided, the front encapsulant layer can alternatively be integrated with dyes or infrared-transparent nanoparticles to achieve a desired appearance. It should be appreciated that front encapsulant layers up to 800 microns thick are possible with lower concentrations of pigment within the encapsulant. The pigment concentration within the 704 front encapsulant layer will scale approximately linearly with the thickness of the 704 front encapsulant layer to achieve a consistent color. In some embodiments, different types of pigment are incorporated into the front and back encapsulant layers. For example, the back encapsulant layer 706 can be impregnated with a pigment that gives it a blue or purple tint, matching the color of a solar cell 708. This prevents color variations between the central regions of the photovoltaic tile occupied by the solar cell 708 and peripheral regions of the photovoltaic tile that extend beyond the area occupied by the solar cell 708. A reinforcing sheet color 710 can also contribute to the overall color of the photovoltaic tile 700 when the back encapsulant layer 706 is not completely opaque to visible light. For example, a surface of b / acnn / eznz / B / Yi reinforcement 710 in contact with the back encapsulant layer 706 may have a dark coloration to further darken an overall color of photovoltaic tile 700.It should be noted that although the 708 solar cell is illustrated as a single solar cell, other configurations are possible. For example, any of the solar cell configurations shown in Figures 2 to 4B are possible. It should be noted that solar cells may have minor color variation, and the pigment used in the back-encapsulating layer may only match one shade of the solar cell color. In some embodiments, multiple different pigments may be mixed non-homogeneously, as will be described in more detail below, to include colors that match multiple shades of the solar cells. Figures 7B to 7D show how a pigment concentration within the front encapsulating layer can allow for variation in the cosmetic appearance of 720, 730, and 740 photovoltaic tiles. Although the singular term "pigment" is used, it should be understood that the term "pigment" can refer to a mixture of multiple pigments. For example, a pigment can be formed from three to five different pigment mixtures combined together to achieve a desired color. In particular, a 722 front encapsulating layer can have a lighter hue than a 732 front encapsulating layer, and a 732 front encapsulating layer can have a lighter hue than a 742 front encapsulating layer. This variation can be achieved by adjusting the amount of pigment within the 722, 732, and 742 front encapsulating layers. For example, using the previously provided concentration of 0.Using 5% as a starting point, the pigment concentrations within the front encapsulating layers 722, 732, and 742 can be 0.45%, 0.5%, and 0.55%, respectively. In some configurations, a smaller amount of variation can be applied using concentrations of 0.475%, 0.5%, and 0.525%. Although an example of only three different concentration variations is provided here, it should be appreciated that any number of concentration variations are possible. For example, it may be desirable to have a larger number of variations for particular colors. It should be appreciated that pigmented photovoltaic tile configurations can range from one in which there are no pigment variations to ten or more pigment variations. Variations in pigment concentration will normally be no more than 10%, as larger pigment concentration variations could result in an undesirable drop in the performance of the photovoltaic tiles or undesirable aesthetics. In some configurations, photovoltaic tiles can be combined into a photovoltaic module that includes two or more photovoltaic tiles similar to the configurations shown in Figures 5A and 5B. In such a photovoltaic module, photovoltaic tiles with different pigment concentrations can be affixed together. Prefabricating photovoltaic tiles into modules can help reduce the amount of labor required to install them on a roof. Providing installers with photovoltaic modules in multiple different color combinations (b / acnn / eznz / B / Yi) helps them create a roof with a cosmetically pleasing, randomized appearance. Figures 8A to 8B show side views of exemplary photovoltaic roof tiles. Figure 8A shows a solar cell 802 integrated within the front encapsulating layer 804 and the back encapsulating layer 806. The front glass cover 808 is positioned over the front encapsulating layer 804 and is textured to help diffuse the light entering and exiting the front glass cover 808. A specific appearance of the front encapsulating layer 804 can be achieved by incorporating a single pigment or a non-homogeneous mixture of multiple pigments into the front encapsulating layer 804. The non-homogeneous mixture of multiple pigments can be used to achieve a more natural variation in the cosmetic appearance of photovoltaic roof tiles. Figure 8B shows a cascaded solar cell comprised of the front encapsulant layer 854 and the rear encapsulant layer 856, sharing characteristics of the cascaded solar cells described in Figures 4A and 4B. As can be seen in Figure 8B, some portions of the cascaded solar cell 852 are slightly closer to the front glass cover 854 than other portions. This results in a varying thickness of the front encapsulant layer across the sun-facing surface of the cascaded solar cell, which can in turn result in slight color variations of the photovoltaic tile over the portions of the tile occupied by the cascaded solar cell 852. In some configurations, the textured surface of the front glass cover 854 can help to mitigate the perception of this color variation.The perception issues that arise from overlapping solar cells can also be mitigated by increasing the thickness of the front encapsulant layer by 856 microns, relative to the amount of height variation resulting from the overlapping solar cell configuration. A front encapsulant layer thickness could be in the range of 600 to 800 microns to reflect the thickness variation inherent in a cascaded solar cell configuration. Figure 8C shows how a clear encapsulant layer 860 could be incorporated between the front encapsulant layer 856 and the sun-facing surface of the solar cells 852. This configuration could allow a uniform amount of pigment to be placed in front of each portion of the solar cells 852, independent of the solar cell overlap geometry. In some embodiments, the clear encapsulant could be sized to be just thick enough to prevent thickness variation in the front encapsulant layer 856. In some embodiments, the thickness of the clear encapsulant layer 860 could be approximately the same as that of the front encapsulant layer 856. In one particular embodiment, the clear encapsulant layer 860 and the front encapsulant layer 856 could each be approximately 450 microns thick. b / cicnn / eznz / B / Yi Figure 9 shows a flow diagram illustrating a manufacturing process for a photovoltaic tile. In step 902, one or more solar cells are received. In some embodiments, a solar cell color is measured to ensure that the color of the solar cells is consistent with the expected color. The solar cells can be arranged in any of several configurations illustrated in Figures 2 to 4B. In step 904, the encapsulating material, such as EVA, can be mixed with a primer pigment to form a first encapsulant layer. The primer pigment can take the form of a mixture of different pigments carefully measured to give the photovoltaic tile a desired cosmetic color appearance. For example, an iron oxide primer pigment could include a particular mixture of FeSO4 and FeSO4 pigments and potentially other iron oxide-based pigments.Alternatively, a dye or nanoparticles can be mixed with encapsulant material to form the first encapsulant layer. In 906, a second encapsulant layer can be formed using encapsulant material and a second pigment. The second pigment can be incorporated into the encapsulant in an amount that causes the second encapsulant layer to match the measured color of the solar cells. In some embodiments, the color of the second encapsulant layer can be adjusted to match an average color of a large group of solar cells, while in other embodiments, the color of the second encapsulant layer can be adjusted to match a particular solar cell or small group of solar cells. In 908, one or more solar cells can be laminated between the first and second encapsulant layers.The lamination process will also generally include sandwiching encapsulant layers between a front glass cover and a backing sheet or glass cover. It should be noted that the amount of pressure and heat applied during the lamination process can affect the overall color of the photovoltaic tile, as excessive pressure or heat could result in undesirable variations in the thickness of one or both of the first and second encapsulant layers. This variation could lead to a photovoltaic tile that has to be discarded due to excessive color variation. The completed photovoltaic tiles can then be pre-assembled into photovoltaic tile modules. In some configurations, the amount of pigment incorporated into each of the photovoltaic tiles that make up the module can vary between five and ten percent. Figure 10 shows an image of an exemplary non-homogeneous mixture of pigments within the encapsulating material. This type of mixture of the first and second types of pigment can be achieved by selecting master batches of pigment that have different properties. Master batches of pigment are typically a concentrated mixture of pigments and / or additives encapsulated during a heating process in a carrier resin, which is then cooled and cut into a granular form. Master batches of pigment are selected to have different viscosities. In some embodiments, the viscosity of the master batches of pigment is varied by adjusting the formulation of the carrier resin used to form the master batches. b / Qcnn / cznz / e / Yi In contrast, industry practice is to minimize differences in pigment masterbatch viscosities to avoid color inconsistencies. When encapsulant material and pigment masterbatches of varying viscosities are mixed together at a controlled mixing temperature, the difference in viscosities at that temperature results in the non-homogeneous color blend illustrated in Figure 10. In some applications, pigments can be blended in a specific way to distribute the first and second pigments in a desired pattern. For example, a blend of encapsulant and pigment masterbatches can be mixed in an extruder at a predetermined speed to achieve a desired pattern before initiating an extrusion operation. The pattern generally depends, at least in part, on the different viscosities and the techniques used to blend the materials together.In some embodiments, the viscosity of the pigment master batches can also be selected to differ from the viscosity of the encapsulant so that portions of the encapsulant remain free of both pigments. Regardless of the composition, once a desired non-homogeneous mixture is achieved, the material can flow through the extruder to form an encapsulating layer with the desired pigment distribution and pattern. Once the encapsulant and pigments cool, the relative positions of the first and second pigments within the encapsulant are fixed. It should be appreciated that although Figure 10 illustrates a mixture of two pigments, in some embodiments, three or more pigments can be mixed together, where a subset of the multiple pigment batches has a different viscosity than the other pigment master batches to achieve the desired non-homogeneous mixture of pigments within the encapsulating layer. In some embodiments, a non-homogeneous pigment blend can be achieved by modifying the extrusion process used to mix the pigments together when the encapsulant layers are formed. Specifically, the extrusion process can be adjusted to reduce the residence time of the encapsulant and pigments within the extruder and / or reduce the mixing intensity within the extruder. Reducing residence time is achieved by accelerating the extruder, and reducing mixing intensity is achieved through careful selection of the extruder screw elements. For example, grooves can be cut around a screw element's flight tip to increase leakage flow through the extruder. In some embodiments, adjustments to the extrusion process can be combined with deliberate variations in the viscosity of the pigment master batches to achieve the desired non-homogeneous pigment blend. Figure 11 shows a distribution of multiple pigments within a photovoltaic tile 1100. Although the image of the photovoltaic tile 1100 is shown in black and white, the shades of gray represent different shades of brown. However, it should be appreciated that different pigment colors and different pigment indices are possible. For example, in some configurations, only a small amount of a second pigment might be mixed with a first pigment to provide only minor color variations in a photovoltaic tile. A smaller amount of the second pigment may also be more desirable where the second pigment is less transparent to visible or infrared light than the first pigment. In some configurations, different photovoltaic tiles or tile modules may include different indices of different pigments, thus providing the homeowner's roof with a greater amount of color variation. The preceding descriptions of the various modalities have been presented for illustrative and descriptive purposes only. They are not intended to be exhaustive or to limit the system to the forms described. Consequently, many modifications and variations will be evident to those skilled in the art. Furthermore, the preceding description is not intended to limit the system. The described modalities include the following points: 1. A photovoltaic tile module, comprising: a photovoltaic tile, comprising: a front glass cover, a front encapsulant layer doped with a first pigment; a rear encapsulant layer doped with a second pigment different from the first pigment corresponding to a color of the plurality of solar cells; and a plurality of solar cells placed between the front and rear encapsulant layers. 2. The photovoltaic tile module as referred to in point 1, wherein the photovoltaic tile is a first photovoltaic tile and the photovoltaic tile module further comprises a second photovoltaic tile electrically and mechanically coupled to the first photovoltaic tile, wherein the front encapsulant layer of the first photovoltaic tile has a larger amount of the first pigment than a front encapsulant layer of the second photovoltaic tile. 3. The photovoltaic tile module as referred to in point 1, further comprising a third photovoltaic tile electrically and mechanically coupled to the second photovoltaic tile, wherein a front encapsulating layer of the third photovoltaic tile has a greater quantity of the first pigment than the front encapsulating layer of the second photovoltaic tile. 4. The photovoltaic tile module as cited in any of points 2 to 3, wherein the front encapsulating layer of the first photovoltaic tile has five to ten percent more of the first pigment than the front encapsulating layer of the second photovoltaic tile. 5. The photovoltaic tile module of any of points 1 to 4, wherein the plurality of solar cells comprises a first side bus bar positioned near one side of a first surface and a second side bus bar positioned near an opposite side of a second surface, and wherein the plurality of solar cells is arranged such that the first side bus bar of a first solar cell overlaps the second side bus bar of an adjacent solar cell, thereby resulting in the plurality of solar cells forming a serially coupled string. 6. The photovoltaic tile module of any of points 1 to 5, wherein an encapsulant layer is disposed between the plurality of solar cells and the front encapsulant layer. 7. The photovoltaic tile module of any of points 1 to 6, wherein the first pigment is an iron oxide-based pigment or a titanium oxide-based pigment. 8. The photovoltaic tile module of any of points 1 to 7, where the front encapsulating layer is between 350 and 800 microns thick. 9. The photovoltaic tile module of any of points 1 to 8, wherein the first pigment is evenly distributed within the front encapsulating layer and creates less than 1% of the material that creates the front encapsulating layer. 10. The photovoltaic tile module of point 1, wherein the first encapsulating layer is doped with a third pigment mixed non-homogeneously with the first pigment. 11. A photovoltaic tile, comprising: a front glass cover; a front encapsulating layer doped with a first pigment; a plurality of solar cells; and a rear encapsulating layer different from the first pigment that corresponds to a color of the plurality of solar cells. 12. The photovoltaic tile of point 11, wherein a respective solar cell comprises a first side bus bar positioned near one side of a first surface and a second side bus bar positioned near an opposite side of a second surface, and wherein the plurality of solar cells is arranged in such a way that the first side bus bar of a first solar cell overlaps with the second side bus bar of an adjacent solar cell, thereby resulting in the plurality of solar cells forming a serially coupled string. 13. The photovoltaic tile of any of points 11 to 12, further comprising a clear encapsulating layer disposed between the front encapsulating layer and the plurality of solar cells. 14. The photovoltaic tile of point 12, where the first encapsulating layer conforms to the superposition geometry of the plurality of solar cells. 15. The photovoltaic tile of point 11, where the first pigment is distributed uniformly across the front encapsulating layer. 16. The photovoltaic tile of point 11, where the front encapsulating layer is between 350 microns and 800 microns. 17. The photovoltaic tile of point 11, where the first pigment has a brown hue and the second pigment has a blue or purple hue. 18. The photovoltaic tile of point 11, where the front encapsulating layer is also doped with a third pigment that is mixed non-homogeneously with the first pigment. b / acnn / eznz / B / Yi 19. The photovoltaic tile of point 11, further comprising a reinforcing sheet having a color that cooperates with a color of the back encapsulating layer to match a color of the plurality of solar cells. 20. The photovoltaic tile of point 11, where the rear encapsulating layer is opaque to visible light.

Claims

1. A photovoltaic tile module, comprising: a front glass cover; a front encapsulating layer doped with a first pigment; a rear encapsulating layer doped with a second pigment different from the first pigment corresponding to a color of the plurality of solar cells; and a plurality of solar cells placed between the front and rear encapsulating layers.

2. The photovoltaic tile module according to claim 1, further characterized in that the photovoltaic tile is a first photovoltaic tile and the photovoltaic tile module further comprises a second photovoltaic tile electrically and mechanically coupled to the first photovoltaic tile, wherein the front encapsulant layer of the first photovoltaic tile has a larger amount of the first pigment than a front encapsulant layer of the second photovoltaic tile.

3. The photovoltaic tile module according to claim 1, further characterized in that an additional third photovoltaic tile is electrically and mechanically coupled to the second photovoltaic tile, wherein a front encapsulating layer of the third photovoltaic tile has a greater amount of the first pigment than the front encapsulating layer of the second photovoltaic tile.

4. The photovoltaic tile module according to any of claims 2 to 3, further characterized in that the front encapsulating layer of the first photovoltaic tile has five to ten percent more of the first pigment than the front encapsulating layer of the second photovoltaic tile.

5. The photovoltaic tile module according to any of claims 1 to 4, further characterized in that the plurality of solar cells comprises a first side bus bar positioned near one side of a first surface and a second side bus bar positioned near an opposite side of a second surface, and wherein the plurality of solar cells is arranged in such a way that the first side bus bar of a first solar cell overlaps the second side bus bar of an adjacent solar cell, thereby resulting in the plurality of solar cells forming a serially coupled string.

6. The photovoltaic tile module in accordance with any of claims 1 to 5, further characterized in that it additionally comprises a clear encapsulant layer disposed between the plurality of solar cells and the front encapsulant layer.

7. The photovoltaic tile module in accordance with any of claims 1 to 6, further characterized in that the first pigment is an iron oxide-based pigment or a titanium oxide-based pigment.

8. The photovoltaic tile module in accordance with any of claims 1 to 7, further characterized in that the front encapsulating layer is between 350 and 800 microns thick.

9. The photovoltaic tile module according to any of claims 1 to 8, further characterized in that the first pigment is uniformly distributed within the front encapsulating layer and creates less than 1% of the material that creates the front encapsulating layer.

10. The photovoltaic tile module according to claim 1, further characterized in that the first encapsulating layer is doped with a third pigment mixed non-homogeneously with the first pigment. 11.- A photovoltaic tile, comprising: a front glass cover; a front encapsulating layer doped with a first pigment; a plurality of solar cells; and a rear encapsulating layer doped with a second pigment different from the first pigment that corresponds to a color of the plurality of solar cells. 12.- The photovoltaic tile according to claim 11, further characterized in that the respective solar cell comprises a first side bus bar positioned near one side of a first surface and a second side bus bar positioned near an opposite side of a second surface, and wherein the plurality of solar cells is arranged in such a way that the first side bus bar of a first solar cell overlaps with the second side bus bar of an adjacent solar cell, thereby resulting in the plurality of solar cells forming a serially coupled string.

13. The photovoltaic tile in accordance with any of claim 12, further characterized in that it additionally comprises a clear encapsulating layer disposed between the front encapsulating layer and the plurality of solar cells.

14. The photovoltaic tile according to claim 12, further characterized in that the first encapsulating layer conforms to the overlapping geometry of the plurality of solar cells.

15. The photovoltaic tile according to claim 11, further characterized in that the first pigment is uniformly distributed throughout the front encapsulating layer.

16. The photovoltaic tile according to claim 11, further characterized in that the front encapsulating layer is between 350 microns and 800 microns.

17. The photovoltaic tile according to claim 11, further characterized in that the first pigment has a brown hue and the second pigment has a blue or purple hue. b / cicnn / eznz / B / Yi 18. The photovoltaic tile according to claim 11, further characterized in that the front encapsulating layer is also doped with a third pigment that is mixed non-homogeneously with the first pigment.

19. The photovoltaic tile according to claim 11, further characterized in that it additionally comprises a reinforcing sheet having a color that cooperates with a color of the back encapsulating layer to match a color of the plurality of solar cells.

20. The photovoltaic tile according to claim 11, further characterized in that the rear encapsulating layer is opaque to visible light.

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