Interlocking lips on building integrable photovoltaic module edges

Provided are novel building integrable photovoltaic (BIP) modules and methods of installing thereof. A module may include a photovoltaic insert having at least one photovoltaic cell, a channel provided on one edge of the insert, and an extension provided on the opposite edge. The extension is configured to fit snugly into a corresponding channel of an adjacent module during installation. The two modules may have the same design and form a photovoltaic array, which may involve interconnecting with additional modules. The interconnection prevents lifting of one module with respect another. Therefore, each module needs to be attached to a building structure only along one edge, while the opposite edge is supported by another module. Attachment to the building structure may be in a concealed area of the module, such as a moisture flap, to prevent exposed though holes. This configuration improves moisture sealing properties of the resulting array.

BACKGROUND

Photovoltaic cells are widely used for electricity generation with one or more photovoltaic cells typically sealed within and interconnected in a module. Multiple modules may be arranged into photovoltaic arrays used to convert solar energy into electricity by the photovoltaic effect. Arrays can be installed on building rooftops and are used to provide electricity to the buildings and to the general grid.

SUMMARY

Provided are novel building integrable photovoltaic (BIP) modules and methods of installing thereof. A module may include a photovoltaic insert having at least one photovoltaic cell, a channel provided on one edge of the insert, and an extension provided on the opposite edge. The extension is configured to fit snugly into a corresponding channel of an adjacent module during installation. Adjacent modules may have the same design and form a photovoltaic array with additional interconnected modules. In certain embodiments, the modules are configured such that a module is attached to a building structure only along one edge, with an opposite edge supported by another module. This configuration may facilitate installment and stability of the resulting array. Also in certain embodiments, attachment to the building structure is concealed, providing improved moisture protection.

In certain embodiments, a BIP module includes a photovoltaic insert having one or more photovoltaic cells, a first edge, and a second edge opposite of the first edge. The BIP module also includes a channel provided on the first edge and an extension provided on the second edge. The extension is configured to fit snugly into a corresponding channel of an adjacent BIP module during installation. Furthermore, the extension may be configured to prevent lifting of the second edge of module with respect to the rest of the module after the installation. The extension may be also configured to form a moisture tight seal with the corresponding channel of the adjacent module. In certain embodiments, an overlap between the extension and the corresponding channel of the adjacent module is between about 5 millimeters and about 20 millimeters wide.

In certain embodiments, an extension is configured to interlock with a corresponding channel of the adjacent module. Such interlocking may prevent the extension from sliding out of the channel. In the same or other embodiments, a channel of the module includes one or more drain openings to allow water to escape from the channel, in particular, when the module is installed on a sloped surface. In certain embodiments, a module also includes a top protrusion provided on the second edge of the insert, i.e., the edge supporting the extension. The top protrusion of the module is configured to be positioned over a corresponding channel of an adjacent module to prevent water ingress into the corresponding channel.

In certain embodiments, a module also includes a moisture flap provided on the first edge of the insert, i.e., the edge supporting the channel, and configured to extend under yet another adjacent module interconnected with the channel of the module. In these embodiments, the channel may be provided on the moisture flap. In certain embodiments, the channel does not extend to side edges of the moisture flap. The moisture flap may be also configured to prevent water from penetrating in between the two modules. In the same or other embodiments, a module also includes one or more seals positioned inside the channel and/or on an edge of the extension. The module may also include one electrical connector positioned inside the channel and another electrical connector positioned on the extension.

In certain embodiments, the channel is a pocket-channel that does not extend to side edges of the module. The pocket-channel includes one or more drain-openings. In specific embodiments, drain-openings are disposed along the side edges of the pocket-channel. A module may include multiple extensions provided on the second edge of the insert. These multiple extensions may be configured to snugly fit into multiple corresponding channels of at least two adjacent building integrable photovoltaic modules during installation.

Provided also is a method for installing an array of BIP modules on a building structure. The method involves providing a first module including a first photovoltaic insert having one or more first photovoltaic cells and a channel provided on a first edge of the first insert. The method also involves providing a second module including a second photovoltaic insert having one or more second photovoltaic cells and an extension provided on a second edge of the second insert. The method then continues with fitting snuggly the extension into the channel. After this fitting, the second edge of the second module can not be lifted up with respect to the first module.

In certain embodiments, the first module may include a moisture flap provided on the first edge. The moisture flap may be attached to the building structure. Some attachment examples include nailing, screwing, gluing, or any other suitable mechanical fastening technique. At least a portion of the second module is positioned over the moisture flap. In the same or other embodiments, snuggly fitting the extension into the channel involves interlocking the two modules. The method may also involve, prior to snuggly fitting the extension into the channel, dispensing a sealing material and/or a bonding material onto the extension of the second module and/or into the channel of the first module. Furthermore, the method may involve attaching a moisture flap of the second module to the building structure. This moisture flap may be provided on an edge opposite of the second edge of the second module. In certain embodiments, attaching this moisture flap of the second module to the building structure is performed after snuggly fitting the extension into the channel of the first module. After attaching the moisture flap to the building structure and after snuggly fitting the extension into the channel, the second module is mechanically secured with respect to the building structure.

In certain embodiments, a method also involves providing a third module including a third photovoltaic insert having one or more third photovoltaic cells and a third extension provided on a third edge of the third photovoltaic insert. The third extension may be then fit snuggly into a channel of the second module. After this fitting, the third extension can not be lifted up with respect to the second module.

These and other aspects of the invention are described further below with reference to the figures.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail to not unnecessarily obscure the present invention. While the invention will be described in conjunction with the specific embodiments, it will be understood that it is not intended to limit the invention to the embodiments.

Building-integrable photovoltaic (BIP) modules are photovoltaic modules specially configured for integration into various parts of building structures, such as rooftops, skylights, or facades. In certain examples, BIP modules are used to replace conventional building materials such as asphalt shingles. Unlike traditional photovoltaic systems, BIP modules often do not require separate mounting hardware. As such, installed BIP modules provide substantial savings over more traditional systems in terms of building materials and labor costs. For example, a traditional asphalt roof shingle may be completely replaced by a type of BIP module referred to as a “photovoltaic shingle.” In certain embodiments, photovoltaic shingle BIP modules are installed on the same base roof structure as asphalt shingles. The BIP modules may have flexible connectors to facilitate installation. A rooftop may be covered completely by photovoltaic shingles or by a combination of the asphalt and photovoltaic shingles. In certain embodiments, BIP modules are shaped like one or a collection of asphalt shingles. In certain embodiments, BIP modules may look and act very much like the asphalt shingles while producing electricity in additional to protecting the underlying building structures from the environment. In certain embodiments, BIP modules may be about 14 (e.g., 13.25) inches by about 40 (e.g., 39.375) inches in size and may be stapled directly to the roof deck through water barrier roofing cloth, for example. Generally, only a portion of the photovoltaic shingle is exposed, while the remaining portion is covered by other shingles. The exposed portion is referred to as the “shingle exposure”, while the covered portion is referred to as the “flap.” For example, the shingle exposure of a 13.25 inch by 39.375 inch shingle may be only about 5 inches wide or, in some embodiments, about 5.625 inches wide. The length of the shingle exposure in some of these embodiments may be 36 inches or about 39.375 inches (if side skirts are not used, for example). Other dimensions of photovoltaic shingles may be used as well. The total weight of a BIP module may range from about 5 pounds to about 25 pounds, for example about 12 pounds.

During installation of BIP modules on a building structure, the modules are mechanically secured to the building structure. The BIP modules described herein are configured in certain embodiments such that the number of through-holes in the modules is minimized. Conventional building materials are generally much lighter than BIP modules and have much fewer attachment requirements. For example, a traditional asphalt shingle is installed by simply nailing its moisture flap to a building structure. The rest of the shingle, which tends to be very light, is supported on the roof by this only connection with one edge of the shingle left unsecured. BIP modules are generally much heavier and are supported at least along two opposite edges of the photovoltaic insert. In certain embodiments, module designs described herein minimize or eliminate a need for through-holes supporting one edge, which may be an edge opposite of the moisture flap. Another edge, which may be an edge attached to the moisture flap, may be supported by an attachment made in a concealed area, such the moisture flap area, and as a result the through holes made in this area are not exposed.

A module may include a photovoltaic insert having at least one photovoltaic cell, a channel provided on one edge of the insert, and an extension provided on the opposite edge. The extension is configured to fit snugly into a corresponding channel of an adjacent module during installation. The two modules may have the same design and form a photovoltaic array, in certain embodiments with additional interconnected modules. The interconnection prevents lifting of one module with respect to another module. In certain embodiments, each module is attached to a building structure only along one edge, while the opposite edge is supported by another module. Attachment to the building structure may be in a concealed area of the module, such as a moisture flap, to prevent exposed though-holes. This configuration improves moisture sealing properties of the resulting array.

To provide a better understanding of various features of BIP modules and methods of integrating connectors with photovoltaic inserts during module fabrication, some examples of BIP modules will now be briefly described.FIG. 1is a schematic cross-sectional end view (line1-1inFIG. 2indicates the position of this cross-section) of a BIP module100in accordance with certain embodiments. BIP module100may have one or more photovoltaic cells102that are electrically interconnected. Photovoltaic cells102may be interconnected in parallel, in series, or in various combinations of these. Examples of photovoltaic cells include copper indium gallium selenide (CIGS) cells, cadmium-telluride (Cd—Te) cells, amorphous silicon (a-Si) cells, micro-crystalline silicon cells, crystalline silicon (c-Si) cells, gallium arsenide multi-junction cells, light adsorbing dye cells, organic polymer cells, and other types of photovoltaic cells.

Photovoltaic cell102has a photovoltaic layer that generates a voltage when exposed to sunlight. In certain embodiments, the photovoltaic layer includes a semiconductor junction. The photovoltaic layer may be positioned adjacent to a back conductive layer, which, in certain embodiments, is a thin layer of molybdenum, niobium, copper, and/or silver. Photovoltaic cell102may also include a conductive substrate, such as stainless steel foil, titanium foil, copper foil, aluminum foil, or beryllium foil. Another example includes a conductive oxide or metallic deposition over a polymer film, such as polyimide. In certain embodiments, a substrate has a thickness of between about 2 mils and 50 mils (e.g., about 10 mils), with other thicknesses also within the scope. Photovoltaic cell102may also include a top conductive layer. This layer typically includes one or more transparent conductive oxides (TCO), such as zinc oxide, aluminum-doped zinc oxide (AZO), indium tin oxide (ITO), and gallium doped zinc oxide. A typical thickness of a top conductive layer is between about 100 nanometers to 1,000 nanometers (e.g., between about 200 nanometers and 800 nanometers), with other thicknesses within the scope.

In certain embodiments, photovoltaic cells102are interconnected using one or more current collectors (not shown). The current collector may be attached and configured to collect electrical currents from the top conductive layer. The current collector may also provide electrical connections to adjacent cells as further described with reference to ofFIG. 5, below. The current collector includes a conductive component (e.g., an electrical trace or wire) that contacts the top conductive layer (e.g., a TCO layer). The current collector may further include a top carrier film and/or a bottom carrier film, which may be made from transparent insulating materials to prevent electrical shorts with other elements of the cell and/or module. In certain embodiments, a bus bar is attached directly to the substrate of a photovoltaic cell. A bus bar may also be attached directly to the conductive component of the current collector. For example, a set of photovoltaic cells may be electrically interconnected in series with multiple current collectors (or other interconnecting wires). One bus bar may be connected to a substrate of a cell at one end of this set, while another bus bar may be connected to a current collector at another end.

Photovoltaic cells102may be electrically and environmentally insulated between a front light-incident sealing sheet104and a back sealing sheet106. Examples of sealing sheets include glass, polyethylene, polyethylene terephthalate (PET), polypropylene, polybutylene, polybutylene terephthalate (PBT), polyphenylene oxide (PPO), polyphenylene sulfide (PPS) polystyrene, polycarbonates (PC), ethylene-vinyl acetate (EVA), fluoropolymers (e.g., polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), ethylene-terafluoethylene (ETFE), fluorinated ethylene-propylene (FEP), perfluoroalkoxy (PFA) and polychlorotrifluoroethane (PCTFE)), acrylics (e.g., poly(methyl methacrylate)), silicones (e.g., silicone polyesters), and/or polyvinyl chloride (PVC), as well as multilayer laminates and co-extrusions of these materials. A typical thickness of a sealing sheet is between about 5 mils and 100 mils or, more specifically, between about 10 mils and 50 mils. In certain embodiments, a back sealing sheet includes a metallized layer to improve water permeability characteristics of the sealing sheet. For example, a metal foil may be positioned in between two insulating layers to form a composite back sealing sheet. In certain embodiments, a module has an encapsulant layer positioned between one or both sealing sheets104,106and photovoltaic cells102. Examples of encapsulant layer materials include non-olefin thermoplastic polymers or thermal polymer olefin (TPO), such as polyethylene (e.g., a linear low density polyethylene, polypropylene, polybutylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, polycarbonates, fluoropolymers, acrylics, ionomers, silicones, and combinations thereof.

BIP module100may also include an edge seal105that surrounds photovoltaic cells102. Edge seal105may be used to secure front sheet104to back sheet106and/or to prevent moisture from penetrating in between these two sheets. Edge seal105may be made from certain organic or inorganic materials that have low inherent water vapor transmission rates (WVTR), e.g., typically less than 1-2 g/m2/day. In certain embodiments, edge seal105is configured to absorb moisture from inside the module in addition to preventing moisture ingression into the module. For example, a butyl-rubber containing moisture getter or desiccant may be added to edge seal105. In certain embodiments, a portion of edge seal105that contacts electrical components (e.g., bus bars) of BIP module100is made from a thermally resistant polymeric material. Various examples of thermally resistant materials and RTI ratings are further described below.

BIP module100may also have a support sheet108attached to back side sealing sheet106. The attachment may be provided by a support edge109, which, in certain embodiments, is a part of support sheet108. Support sheets may be made, for example, from rigid materials. Some examples of rigid materials include polyethylene terephthalate (e.g., RYNITE® available from Du Pont in Wilmington, Del.), polybutylene terephthalate (e.g., CRASTIN® also available from Du Pont), nylon in any of its engineered formulations of Nylon 6 and Nylon 66, polyphenylene sulfide (e.g., RYTON® available from Chevron Phillips in The Woodlands, Tex.), polyamide (e.g., ZYTEL® available from DuPont), polycarbonate (PC), polyester (PE), polypropylene (PP), and polyvinyl chloride (PVC) and weather able engineering thermoplastics such as polyphenylene oxide (PPO), polymethyl methacrylate, polyphenylene (PPE), styrene-acrylonitrile (SAN), polystyrene and blends based on those materials. Furthermore, weatherable thermosetting polymers, such as unsaturated polyester (UP) and epoxy, may be used. The properties of these materials listed above may be enhanced with the addition of fire retardants, color pigments, anti-tracking, and/or ignition resistant materials. In addition, glass or mineral fibers powders and/or spheres may be used to enhance the structural integrity, surface properties, and/or weight reduction. The materials may also include additives such as anti-oxidants, moisture scavengers, blowing or foaming agents, mold release additives, or other plastic additives.

In certain embodiments, support sheet108may be attached to back sheet106without a separate support edge or other separate supporting element. For example, support sheet108and back sheet106may be laminated together or support sheet108may be formed (e.g., by injection molding) over back sheet106. In other embodiments back sealing sheet106serves as a support sheet. In this case, the same element used to seal photovoltaic cells102may be positioned over and contact a roof structure (not shown). Support sheet108may have one or more ventilation channels110to allow for air to flow between BIP module100and a building surface, e.g., a roof-deck or a water resistant underlayment/membrane on top of the roof deck. Ventilation channels110may be used for cooling BIP module during its operation. For example, it has been found that each 1° C. of heating from an optimal operating temperature of a typical CIGS cell causes the efficiency loss of about 0.33% to 0.5%.

BIP module100has one or more electrical connectors112for electrically connecting BIP module100to other BIP modules and array components, such as an inverter and/or a battery pack. In certain embodiments, BIP module100has two electrical connectors112positioned on opposite sides (e.g., the short or minor sides of a rectangular module) of BIP module100, as for example shown inFIGS. 1 and 2, for example. Each one of two electrical connectors112has at least one conductive element electrically connected to photovoltaic cells102. In certain embodiments, electrical connectors112have additional conductive elements, which may or may not be directly connected to photovoltaic cells102. For example, each of two connectors112may have two conductive elements, one of which is electrically connected to photovoltaic cells102, while the other is electrically connected to a bus bar (not shown) passing through BIP module100. This and other examples are described in more detail in the context ofFIGS. 6 and 7. In general, regardless of the number of connectors112attached to BIP module100, at least two conductive elements of these connectors112are electrically connected to photovoltaic cells102.

FIG. 2is a schematic top view of BIP module100in accordance with certain embodiments. Support sheet108is shown to have a side skirt204and a top flap206extending beyond a BIP module boundary202. Side skirt204is sometimes referred to as a side flap, while top flap206is sometimes referred to as a top lap. In certain embodiments, BIP module100does not include side flap204. BIP module boundary202is defined as an area of BIP module100that does not extend under other BIP modules or similar building materials (e.g., roofing shingles) after installation. BIP module boundary202includes photovoltaic cells102. Generally, it is desirable to maximize the ratio of the exposed area of photovoltaic cells102to BIP module boundary202in order to maximize the “working area” of BIP module100. It should be noted that, after installation, flaps of other BIP modules typically extend under BIP module boundary202. In a similar manner, after installation, side flap204of BIP module100may extend underneath another BIP module positioned on the left (in the same row) of BIP module100creating an overlap for moisture sealing. Top flap206may extend underneath one or more BIP modules positioned above BIP module100. Arrangements of BIP modules in an array will now be described in more detail with reference toFIGS. 3 and 4.

FIG. 3illustrates a photovoltaic array300or, more specifically a portion of a photovoltaic array, which includes six BIP modules100a-100farranged in three different rows extending along horizontal rooflines in accordance with certain embodiments. Installation of BIP modules100a-100fgenerally starts from a bottom roofline302so that the top flaps of BIP modules100a-100fcan be overlapped with another row of BIP modules. If a side flap is used, then the position of the side flap (i.e., a left flap or a right flap) determines which bottom corner should be the starting corner for the installation of the array. For example, if a BIP module has a top flap and a right-side flap, then installation may start from the bottom left corner of the roof or of the photovoltaic array. Another BIP module installed later in the same row and on the right of the initial BIP module will overlap the side flap of the initial BIP module. Furthermore, one or more BIP modules installed in a row above will overlap the top flap of the initial BIP module. This overlap of a BIP module with a flap of another BIP module creates a moisture barrier.

FIG. 4is a schematic illustration of a photovoltaic array400installed on a rooftop402of a building structure404for protecting building structure404from the environment as well as producing electricity in accordance with certain embodiments. Multiple BIP modules100are shown to fully cover one side of rooftop402(e.g., a south side or the side that receives the most sun). In other embodiments, multiple sides of rooftop402are used for a photovoltaic array. Furthermore, some portions of rooftop402may be covered with conventional roofing materials (e.g., asphalt shingles). As such, BIP modules100may also be used in combination with other roofing materials (e.g., asphalt shingles) and cover only a portion of rooftop. Generally, BIP modules100may be used on steep sloped to low slope rooftops. For example, the rooftops may have a slope of at least about 2.5-to-12 or, in many embodiments, at least about 3-to-12.

Multiple BIP modules100may be interconnected in series and/or in parallel with each other. For example, photovoltaic array400may have sets of BIP modules100interconnected in series with each other (i.e., electrical connections among multiple photovoltaic modules within one set), while these sets are interconnected in parallel with each other (i.e., electrical connections among multiple sets in one array). Photovoltaic array400may be used to supply electricity to building structure404and/or to an electrical grid. In certain embodiments, photovoltaic array400includes an inverter406and/or a battery pack408. Inverter406is used for converting a direct current (DC) generated by BIP modules100into an alternating current (AC). Inverter406may be also configured to adjust a voltage provided by BIP modules100or sets of BIP modules100to a level that can be utilized by building structure404or by a power grid. In certain embodiments, inverter406is rated up to 600 volts DC input or even up to 1000 volts DC, and/or up to 10 kW power. Examples of inverters include a photovoltaic static inverter (e.g., BWT10240—Gridtec 10, available from Trace Technologies in Livermore, Calif.) and a string inverter (e.g. Sunny Boy ®.2500 available from SMA America in Grass Valley, CA). In certain embodiments, BIP modules may include integrated inverters, i.e., “on module” inverters. These inverters may be used in addition to or instead of external inverter406. Battery pack408is used to balance electric power output and consumption.

FIG. 5is a schematic representation of a photovoltaic module insert500illustrating photovoltaic cells504electrically interconnected in series using current collectors/interconnecting wires506in accordance with certain embodiments. Often individual cells do not provide an adequate output voltage. For example, a typical voltage output of an individual CIGS cell is only between 0.4V and 0.7V. To increase voltage output, photovoltaic cells504may be electrically interconnected in series for example, shown inFIG. 5and/or include “on module” inverters (not shown). Current collectors/interconnecting wires506may also be used to provide uniform current distribution and collection from one or both contact layers.

As shown inFIG. 5, each pair of photovoltaic cells504has one interconnecting wire positioned in between the two cells and extending over a front side of one cell and over a back side of the adjacent cell. For example, a top interconnecting wire506inFIG. 5extends over the front light-incident side of cell504and under the back side of the adjacent cell. In the figure, the interconnecting wires506also collect current from the TCO layer and provide uniform current distribution, and may be referred to herein as current collectors. In other embodiments, separate components are used to for current collection and cell-cell interconnection. End cell513has a current collector514that is positioned over the light incident side of cell513but does not connect to another cell. Current collector514connects cell513to a bus bar510. Another bus bar508may be connected directly to the substrate of the cell504(i.e., the back side of cell504). In another embodiment, a bus bar may be welded to a wire or other component underlying the substrate. In the configuration shown inFIG. 5, a voltage between bus bars508and510equals a sum of all cell voltages in insert500. Another bus bar512passes through insert500without making direct electrical connections to any photovoltaic cells504. This bus bar512may be used for electrically interconnecting this insert in series without other inserts as further described below with reference toFIG. 6. Similar current collectors/interconnecting wires may be used to interconnect individual cells or set of cells in parallel (not shown).

BIP modules themselves may be interconnected in series to increase a voltage of a subset of modules or even an entire array.FIG. 6illustrates a schematic electrical diagram of a photovoltaic array600having three BIP modules602a-602cinterconnected in series using module connectors605a,605b, and606in accordance with certain embodiments. A voltage output of this three-module array600is a sum of the voltage outputs of three modules602a-602c. Each module connector605aand605bshown inFIG. 6may be a combination of two module connectors of BIP modules602a-602c. These embodiments are further described with reference toFIGS. 8A-8C. In other words, there may be no separate components electrically interconnecting two adjacent BIP modules, with the connection instead established by engaging two connectors installed on the two respective modules. In other embodiments, separate connector components (i.e., not integrated into or installed on BIP modules) may be used for connecting module connectors of two adjacent modules.

Module connector606may be a special separate connector component that is connected to one module only. It may be used to electrically interconnect two or more conductive elements of the same module connector.

Sometimes BIP modules may need to be electrically interconnected in parallel.FIG. 7illustrates a schematic electrical diagram of a photovoltaic array700having three BIP modules702a-702cinterconnected in parallel using module connectors705aand705bin accordance with certain embodiments. Each module may have two bus bars extending through the module, i.e., a “top” bus bar711and a “bottom” bus bar713as shown inFIG. 7. Top bus bars711of each module are connected to right electrical leads704a,704b, and704cof the modules, while bottom bus bars713are connected to left electrical leads703a,703b, and703c. A voltage between the top bus bars711and bottom bus bars713is therefore the same along the entire row of BIP modules702a-702c.

FIG. 8Ais a schematic cross-sectional side view of two connectors800and815configured for interconnection with each other, in accordance with certain embodiments. For simplicity, the two connectors are referred to as a female connector800and a male connector815. Each of the two connectors800and815is shown attached to its own photovoltaic insert, which includes photovoltaic cells802and one or more sealing sheets804. Connectors800and815include conductive elements808band818b, respectively, which are shown to be electrically connected to photovoltaic cells802using bus bars806and816, respectively.

In certain embodiments, a conductive element of one connector (e.g., conductive element808bof female connector800) is shaped like a socket/cavity and configured for receiving and tight fitting a corresponding conductive element of another connector (e.g., conductive element818bof male connector815). Specifically, conductive element808bis shown forming a cavity809b. This tight fitting and contact in turn establishes an electrical connection between the two conductive elements808band818b. Accordingly, conductive element818bof male connector815may be shaped like a pin (e.g., a round pin or a flat rectangular pin). A socket and/or a pin may have protrusions (not shown) extending towards each other (e.g., spring loaded tabs) to further minimize the electrical contact resistance by increasing the overall contact area. In addition, the contacts may be fluted to increase the likelihood of good electrical contact at multiple points (e.g., the flutes guarantee at least as many hot spot asperities of current flow as there are flutes).

In certain embodiments, connectors do not have a cavity-pin design as shown inFIGS. 8A-8C. Instead, an electrical connection may be established when two substantially flat surfaces contact each other. Conductive elements may be substantially flat or have some topography designed to increase a contact surface over the same projection boundary and/or to increase contact force at least in some areas. Examples of such surface topography features include multiple pin-type or rib-type elevations or recesses.

In certain embodiments, one or more connectors attached to a BIP module have a “touch free” design, which means that an installer can not accidently touch conductive elements or any other electrical elements of these connectors during handling of the BIP module. For example, conductive elements may be positioned inside relatively narrow cavities. The openings of these cavities are too small for a finger to accidently come in to contact with the conductive elements inside the cavities. One such example is shown inFIG. 8Awhere male connector815has a cavity819bformed by connector body820around its conductive pin818b. While cavity819bmay be sufficiently small to ensure a “touch free” designed as explained above, it is still large enough to accommodate a portion of connector body810of female connector800. In certain embodiments, connector bodies810and820have interlocking features (not shown) that are configured to keep the two connectors800and815connected and prevent connector body810from sliding outs of cavity819b. Examples of interlocking features include latches, threads, and various recess-protrusion combinations.

FIG. 8Bis schematic plan view of female connector800and male connector815, in accordance with certain embodiments. Each connector800,815is shown with two conductive elements (i.e., conductive sockets808aand808bin connector800and conductive pins818aand818bin connector815). One conductive element (e.g., socket808band pin818b) of each connector is shown to be electrically connected to photovoltaic cells802. Another conductive element of each connector800,815may be connected to bus bars (e.g., bus bars809and819) that do not have an immediate electrical connection to photovoltaic cells802of their respective BIP module (the extended electrical connection may exist by virtue of a complete electrical circuit).

As shown, sockets808aand808bmay have their own designated inner seals812aand812b. Inner seals812aand812bare designed to provide more immediate protection to conductive elements808aand818aafter connecting the two connectors800,815. As such, inner seals812aand812bare positioned near inner cavities of sockets808aand808b. The profile and dimensions of pins818aand818bclosely correspond to that of inner seals812aand812b. In the same or other embodiments, connectors800,815have external seals822aand822b. External seals822aand822bmay be used in addition to or instead of inner seals812aand812b. Various examples of seal materials and fabrication methods are described below in the context ofFIG. 9.FIG. 8Cis schematic front view of female connector800and male connector815, in accordance with certain embodiments. Connector pins818aand818bare shown to have round profiles. However, other profiles (e.g., square, rectangular) may also be used for pins818aand818band conductive element cavities808aand808b.

FIG. 9is a schematic representation of a BIP array900including three BIP modules902a,902b, and902cin accordance with certain embodiments. BIP array900is shown positioned on a sloped building structure904. In other embodiments, BIP modules902a,902b, and902cmay be positioned on a substantially horizontal building structure. BIP modules902a,902b, and902cmay be attached to building structure904at their respective moisture flaps908a,908b, and908c. For example, moisture flaps908a,908b, and908cmay be nailed, screwed, glued, or otherwise mechanically attached to building structure904. Each of moisture flaps908a,908b, and908cextends under at least a portion of an adjacent module to enhance a moisture seal. In certain embodiments, a moisture flap extends under at least about 50% of the module's width (i.e., the module's dimension extending along the roof slope) of the module positioned in the upper adjacent row. This degree of the overlap is needed to ensure that any gap that may exist in between each pair of the modules in one row fully overlaps with a moisture flap of the module in the lower adjacent row. For example, the moisture flap may be at least about two inches wider than the corresponding photovoltaic portion, which remains exposed after installation. In certain embodiments, the module may also include one or more side flaps. These flaps extend in a direction perpendicular to the moisture flap and are attached to side edges of the module. When at least one side flap is present, then the moisture flap may be narrows and extend under only a part of the photovoltaic portion. As shown inFIG. 9, moisture flap908aextends under a portion of module902c, while moisture flap908bextends under a portion of module902a. A puncture hole through a moisture flap of a BIP module to attach it to a building structure underlies an adjacent module and generally does not cause moisture sealing problems.

Attachment of a moisture flap of a module to a building structure provides support to an edge of the insert attached to the flap with respect to the building structure. A channel or an extension may be provided along that edge and may be similarly supported with respect to the building structure. For example, moisture flap908bis provided on the same edge of module902bas channel904b. Attaching moisture flap908bto building structure904will also provide support to channel904b. At the same time, this attachment does not expose any through-holes that may be needed for the attachment because moisture flap908bis fully covered by a portion of module902a.

An edge of the module opposite of the moisture flap may be supported by an adjacent module without a need to make a direct connection between the module and building structure. More specifically, two adjacent modules may interconnect to support an edge of one module. In certain embodiments, one module has an extension provided on its edge while another module has a channel configured for snugly fitting around the extension of the first module.FIG. 9illustrates an extension906aof module902ainserted into channel904bof module902b. Channel904bprevents extension906afrom lifting with respect to at least module902b.

In certain embodiments, a BIP module has a channel provided on one edge of the photovoltaic insert and an extension provided on the opposite edge of the insert. A combination of an insert, channel, extension, moisture flap, electrical connectors is referred to as a module. Various examples of photovoltaic inserts and connectors are described above. The extension is configured to fit snugly into a corresponding channel of an adjacent module during installation. The extension is also configured to prevent lifting of the edge supporting the extension with respect to the adjacent module after the installation. The adjacent module and other modules in a photovoltaic array may have similar extension-channel designs.

In certain embodiments, two interconnected modules may be offset with respect to each other. For example, a channel extending throughout the entire edge of one module may be interconnected only with a portion of the extension that also extends throughout the entire edge of the other module. The channel and extension only partially overlap. The rest of the channel may be interconnected with another extension of a third module and so on. One such example is further described below in the context ofFIG. 10B.

FIG. 10Ais a schematic representation of an interconnection of a channel1004aof one BIP module1002awith an extension1006bof another BIP module1002bin accordance with certain embodiments. While various features are discussed in the context of only portions of modules1002aand1002b, one having ordinary skill in the art would understand that the corresponding features may be present on other ends of modules1002aand1002bas generally shown inFIG. 9. BIP modules1002aand1002binclude one or more photovoltaic cells1003aand1003brespectively.

Extension1006bis shown snugly fit into channel1004a. In certain embodiments, extension1006bis configured to form a moisture tight seal with channel1004asuch that water from rain or other precipitation can not penetrate through the seal. In the same or other embodiments, module1002aalso include a moisture flap1008aprovided on the same edge as channel1004a. Moisture flap1008ais configured to extend under at least a portion of adjacent module1002b. It also prevents water from penetrating in between the two modules and may be used for attachment to a building structure as described above. In certain embodiments, an overlap between extension1006band channel1004ais between about 5 millimeters and about 20 millimeters.

Module1002amay have one or more flow channels1012athat can be used to drain water from channel1004aas well as for other purposes. For example, if a module is installed on a sloped surface as shown inFIGS. 9 and 10, water may flow out of channel1004aunder its own gravity using one or more flow channels1012a. Flow channels1012amay also be used for accessing extension1006bduring installation and repair while module1002ais interconnected with module1002b. For example, an interlocking mechanism may be positioned around a flow channel and may be accessed through a flow channel when the two modules need to be separated. Flow channels1012amay have closed or open channel structures and extend toward the front surface of the module. An example of the closed channel structure is shown inFIG. 10A. In another example, flow channels may be or include a set of cuts in a top lip1014a(that partially defines channel1004a) forming open channel structures. Flow channels1012agenerally do not extend over photovoltaic cells1003ato prevent interference with light.

FIG. 10Bis a schematic top view of five BIP modules1022a-1022eforming two interconnected rows in accordance with certain embodiments. Specifically, modules1022aand1022bform a top row (or portion thereof), while modules1022c,1022d, and1022eform a bottom row (or portion thereof). Modules in one row are interconnected with modules in another row using a combination of a channel and an extension. This configuration is illustrated inFIG. 10Cin more detail showing two BIP modules1022band1022c. An extension1046bof module1022bis inserted into a channel1044eof module1022e. The tip of extension1046bmay touch the bottom of channel1044eforming an interface line1048. The same interface is shown with a dotted line1042inFIG. 10B. In certain embodiments, this interface may have some spacing that is used for draining water out of the channel. An interface does not necessarily require touching between the channel and extension components in a particular location. In general, an interface may be provided by a seal or other modules' components and/or be positioned in locations other than the bottom of the channel.

As shown inFIG. 10B, modules in one row may be offset with respect to modules in another row. The offset results in one module connected to two other modules in an adjacent row. For example, an extension of module1022bis inserted a channel of module1022eand a channel of module1022d. In a similar manner, the channel of module1022dreceives extensions of modules1022aand1022b. This offset may help to improve moisture sealing and/or mechanical integrity characteristics of the entire array.

Water may be drained from the interface between two rows using flow channels, which are described above in the context ofFIG. 10A.FIG. 10Billustrates two flow channels1034dand1036d, which may be open channels formed by cut outs in the top lip of the channel. Draining may be also achieved by providing side openings, such as one at an interface1040located at the junction of modules1022dand1022e. Such a side opening at interface1040may be used to drain water from any spacing between any of the modules. In certain embodiments, a plug1030is disposed to prevent water flowing within the spacing past this plug. A plug may be needed to prevent water from flowing behind the modules and toward the building structure if, for example, multiple channels are not interconnected to form a continuous sealed channel. Plug1030may be a part of module1022d, e.g., a protrusion in its channel, or a part of module1022b, e.g., a protrusion on the extension. Plug1030or similar features may be also used to reference one module with respect to another.

In certain embodiments, module1002balso includes a top protrusion1010bprovided on the same edge of module as extension1006b. Top protrusion1010bis configured extend over channel1004aof adjacent module1002aand may be used to further enhance a moisture seal and/or mechanical interconnection between modules1002aand1002b. Top protrusion1010bmay be made from flexible material and exert a downward pressure on channel1004ain the installed position to ensure sealing.

In certain embodiments, an extension is configured to interlock with a channel of an adjacent module. For example, the channel and extension may have corresponding protrusions extending towards each other during the installation and allowing the extension to be inserted into the channel but not slid out of the channel.FIG. 10Dillustrates a set of interlocking features1064aand1066bin accordance with certain embodiments. Specifically, interlocking feature1064ais an extension positioned on top lip1014athat forms channel1004a. Interlocking feature1066bis a recess in extension1006b. When extension1006bis inserted into channel1004a, top lip1014aslightly flexes upwards allowing features1064aand1066bto interlock. Once engaged, interlocking features1064aand1066bprevent extension1006bfrom sliding out of channel1004a. Interlocking features may be also positioned on a top flap, a moisture flap, and/or other components of the module. Furthermore, interlocking features may be also used to prevent two modules from sliding in a direction parallel to the extension or the channel, in which case a locking surface formed by a protrusion and extension should extend in a direction perpendicular to the channel length. As further explained below with reference toFIGS. 11A-11D, in certain embodiments, interlocking along this direction may be accomplished by a series of pocket-channel and individual tab combinations.

In certain embodiments, a module also includes one or more seals positioned inside the channel and/or on an edge of the extension. A seal may be installed during fabrication of the module or during its installation. For example, a sealing material and/or bonding material may be dispensed onto an extension and/or into a channel prior to interconnecting the two.

FIG. 10Eis a schematic side view of another BIP module1050in accordance with certain embodiments. Module1050includes a photovoltaic insert1052containing one or more interconnected cells. Photovoltaic insert1052may be configured similar to other photovoltaic inserts described in this document. For example, photovoltaic insert1052may include one or more CIGS cells interconnected in series with each other. Photovoltaic insert1052includes typically include one or more insulating sheets (e.g., glass sheets) protecting the cells from the environment. The insulating sheets may be enclosed into a plastic overmold as shown inFIG. 10E. Various examples of overmold configurations and materials are described elsewhere in this document. Other configurations for supporting photovoltaic insert1052with respect to other module's components are possible.

Module1050also includes a moisture flap1054extending up the roofline from photovoltaic insert1052. As described above, most of moisture flap1054will be positioned under another module after installation of the array. As such, moisture flap1054may have though holes and/or may be used for attachment to a building structure. Moisture flap1054may form a continuous body with the overmold as shown in FIG.10E. Moisture flap1054may be made from various rigid or semi-rigid materials listed above in order to provide better support to photovoltaic insert1052. At the interface of moisture flap1054and photovoltaic insert1052, module1050includes a channel1056. Channel1056is configured for receiving an extension of another module during installation of an array and for providing mechanical support to this extension with respect to module1050. Furthermore, during installation, the channel portion of module1056is secured with respect to a building structure, e.g., through moisture flap. As such, the extension of the module is also secured with respect to the building structure even though the photovoltaic portion of this module does not have direct attachment to the building structure.

Channel1056is an open channel. It may extend along the entire length of the module (i.e., a direction perpendicular to the side view illustrated inFIG. 10E). In other embodiments, it may extend along just a portion of this length similar to a tab-pocket design shown inFIG. 11. An opening of channel1056faces down the roof line, which allows water to escape from channel. Water is then directed over the front side of photovoltaic insert1052, for example. As such, module1050is configured to provide electricity and protect the building structure from the environment.

A bottom edge of photovoltaic module1050includes an extension1058configured for inserting into a channel of another module (like channel1056of module1050). The bottom edge is defined as an edge opposite of moisture flap1054. At the same time, extension1058protrudes up the roof line to fit into the channel opening, which faces down the roof line as explained above. Furthermore, extension1058is positioned on the back side of module1050, such as underneath photovoltaic insert1052as shown inFIG. 10E. However, other arrangement and locations of the extension are possible. A combination of channel1056and extension1056position on module1050allows forming a continuous mechanically interconnected array of modules as shown inFIG. 10Fand will now be explained in more detail.

FIG. 10Fis a schematic side view of an assembly including four BIP modules1050a,1050b,1050c, and1050din accordance with certain embodiments. The four modules are mechanically interconnected with each other providing a continuous seal to an underlying building structure (not shown) as well as providing some mechanical supports to each other, more specifically, to bottom edges of adjacent modules. For example, modules1050a,1050b,1050c, and1050dmay be connected to the building structure in their moisture flap areas, while their bottom portions corresponding to the photovoltaic inserts are not directly connected. To provide support to their bottom portions, extensions and channels of these modules are engaged. Specifically, an extension of module1050dis engaged with a channel of module1050c; an extension of module1050cis engaged with a channel of module1050b; an extension of module1050bis engaged with a channel of module1050a. This assembly may continue up and/or down the roof line and include any number of modules. These attachments will now be further explained with reference toFIG. 10G.

FIG. 10Gis an expanded schematic view of engaged portions of two modules1050cand1050dfrom the set presented inFIG. 10F. Specifically, this view illustrates extension1058dof module1050dengaged with channel1056cof module1050c. During installation, extension1058dis inserted into channel1056cforming this engagement. This combination of extension1058dand channel1056cmay include interlocking features similar to the ones described with reference toFIG. 10D, sealing features, and/or bonding features. Furthermore, modules1050cand1050dare attached to the building structure (e.g., at their moisture flap areas) and maintain their relative positions, which keeps extension1058dand channel1056cengaged. In certain embodiments, some elements of extension1058dand/or channel1056cmay be made from semi-rigid material that allows some flexibility to these elements and allows separating extension1058dfrom channel1056c, while the respective moisture flap areas are still attached to the building structure. This feature may be used for replacing modules in the installed array (e.g., when one modules breaks). At the same time, these and other elements of extension1058dand/or channel1056should be sufficiently rigid to prevent separation due to gusty winds and/or other environmental factors.

Extension1058dand channel1056cmay be configured in such a way that module1050ddoes not interfere with (e.g., does not shade) the photovoltaic cells in photovoltaic portion1052cof module1050c. The bottom edge of module1050dis shown with a sealing edge1059d, which may be pressed against the front surface of module1050cduring installation of the array to provide a seal to the engagement. In certain embodiments, sealing edge1059dis more flexible than extension1058d.

FIG. 11Ais a schematic representation of a photovoltaic assembly including three modules1102a,1102b, and1102carranged into two rows prior to engaging module1102awith modules1102band1102c. Modules1102band1102crepresent a part of one row, while module1102arepresents a part of an adjacent upper row. The up and down directions (as in “upper row” and “lower row”) are defined with respect to the slope of the roof. Module1102aincludes a photovoltaic portion1104aand a moisture flap1106aattached to photovoltaic portion1104a. Photovoltaic portion1104aincludes one or more photovoltaic cells1108a, various examples and configurations of which are described above. Moisture flap1106aextends in an upward direction from photovoltaic portion1104aafter installation of module1102a. Moisture flap1106ais configured to extend at least under one or two photovoltaic portions of the modules in the upper adjacent row. For example, moisture flaps of modules1102band1102cwill extend under at least under photovoltaic portion1104aof module1102aafter installation. In certain embodiments, these moisture flaps also extend under at least a portion of moisture flap1106ato ensure that any gap in between two modules is sealed with a moisture flap extending under this gap. Moisture flap1106amay include edge protrusions1114aextending in a direction away from a building structure. Edge protrusions1114aare configured to prevent moisture from escaping the moisture flap area through two side edges of moisture flap1106aand direct all moisture towards the top surface of the photovoltaic portion1104a. As described above, the photovoltaic portion1104aincludes a sealing sheet such as a glass panel. The moisture flows over this sheet down the roof.

Module1102ais shown with four individual tabs1110a-1,1110a-2,1110a-3, and1110a-4attached to photovoltaic portion1104aand extending away from moisture flap1106a. In general, any number of tabs can be used, e.g., one tab, two tabs, three tabs, four tabs, five tabs, etc. An example with one continuous tab extending along the entire edge of the photovoltaic portion is described above with reference toFIGS. 10B and 10C. Module1102ais also shown with four individual pocket-channels1112a. These channels do not extend to side edges of module1102a(i.e., the edges carrying edge protrusions1114in the example shown inFIG. 11A). As such, there is less risk that any water collected in pocket-channels1112awill migrate to these edges of module1102aand possibly under module1102a.

Four individual tabs1110a-1,1110a-2,1110a-3, and1110a-4are configured for insertion into corresponding pocket-channels of adjacent modules. As shown inFIG. 11A, tabs1110a-1,1110a-2,1110a-3, and1110a-4are aligned for insertion into pocket-channels1112b-3and1112b-4of module1102band pocket channels1112c-1and1112c-2of module1102c. Specifically, tab1110a-1is aligned with respect to pocket-channel1112b-3, tab1110a-2is aligned with respect to pocket-channel1112b-4, tab1110a-3is aligned with respect to pocket-channel1112c-1, and tab1110a-4is aligned with respect to pocket-channel1112c-2. One having ordinary skills in the art would understand that other alignment options are possible as well.

FIG. 11Billustrates a schematic expanded view of one tab1100a-2aligned with respect to pocket-channel1112b-4prior to engaging tab1100a-2and pocket-channel1112b-4or more specifically prior to inserting tab1100a-2into pocket-channel1112b-4. Pocket-channel1112b-4is shown with two drain-openings1120barranged along opposite side edges of the channel, which is illustrated in more detail inFIG. 11Dcorresponding to a cross-section “B-B” shown with a dotted line inFIG. 11B. Pocket-channel1112b-4is also shown to have a lip1122bpartially extending along the pocket-channel in between two drain-openings1120b. Lip1122bforms an open cavity1124b(as shown inFIG. 11C), which is configured for receiving a portion of tab1110a-2. The tabs may be made from a semi-rigid material that is capable of bending to conform to the shape of the pocket-channels and open-cavities during insertion. The tabs and lips may include interlocking features similar to the ones described with reference toFIG. 10D. As shown inFIG. 11D, drain-openings1120ballow water to escape from open cavity1124b. In certain embodiments, the bottom of the open cavity may be sloped towards the drain openings.

FIG. 12is a flowchart corresponding to a process1200of installing a building integrable photovoltaic (BIP) array of BIP modules on a building structure in accordance with certain embodiments. Process1200may start with an operation1202that involves providing a first BIP module having an insert and a channel provided on one edge of the insert. Various examples of BIP modules are described above. The module provided in this operation may also have an extension, which may be already interconnected to another module.

Process1200may proceed with attaching a moisture flap of the provided module to the building structure in an operation1204. For example, a moisture flap may be nailed, screwed, glued, or mechanically attached using other suitable technique to the building structure. In certain embodiments, a provided module does not have a moisture flap and other components of the module positioned near the channel edge are attached to the building structure.

At some point during installation process1200, another BIP module is provided (block1206). This second module has an insert and an extension provided on one edge of the insert. This module may also have a channel provided on the opposite edge of the insert for interconnection with additional modules. In general, the first module provided in operation1202and the second module provided in operation1206may have the same design.

In certain embodiments, a sealing material and/or an adhesive material is dispensed into the channel of the first module or onto the extension of the second module in an optional operation1208. Some examples of such materials include Dow Corning in Midland, Mich.: silicone adhesives (part numbers 3-1595 and 3-1595HP), thixotropic adhesive (part number 3-6265), silane and siloxane based adhesives (part number 4-8012), primer-less silicone adhesive (part number 866), heat cured one part adhesive (part number SE1771), thixotropic fast low temperature cure adhesive (part number EA-6054), two part translucent heat cure adhesive (part number SE 1700), Sylgard® 577 primer-less silicone adhesive, PV-804 Neutral Sealant, and two-part controlled-volatility (CV) grade adhesive (part number SE 1720).

Process1200may proceed with snuggly fitting the extension of the second module into the channel of the first module in operation1210. This operation mechanically interconnects the two modules, such that the extension edge of the second module can not be lifted up with respect to the first module. If the first module has been previously attached to the building structure (e.g., in operation1204), then the extension edge of the second module is now secured with respect to the building structure as well. At the same time, the opposite edge of the second module remains unsecured.

In operation1210, at least a portion of the second module may be positioned over a moisture flap of the first module. For example, a moisture flap may have through-holes made during attachment of the moisture flap to the building structure in operation1204. Positioning the second module over this moisture flap may help to further isolate these though holes from moisture.

In certain embodiments, an extension of the second module and a channel of the first module may have interlocking features. In these embodiments, snuggly fitting the extension into the channel also involves interlocking the two modules. The modules may be interlocked in various directions. For example, the modules may be interlocked to prevent the extension from sliding out of the channel. In the same or another embodiment, the modules may be interlocked to prevent the extension from sliding within the channel in a direction parallel to the channel's length.

A moisture flap of the second module may be then attached to the building structure in operation1212. This operation may be similar to operation1204described above. In certain embodiments, the moisture flap of the second module is attached to the building structure before snugly fitting the extension into the channel with operation1212performed before operation1210. After completing operations1210and1212, the second module may not be lifted up with respect to the building structure.

Some operations (e.g., operations1204,1206,1208,1210, and1212) may be repeated for additional modules (block1214). For example, a third module may be provided. This module may include an insert and a third extension provided on the edge of the insert. This third extension is then fit snugly into a channel of the second module. After this fitting, the third extension can not be lifted up with respect to the second module. A moisture flap of the third module may be attached to the building structure.