Hinges are commonly used in folding devices. For example, board games often include a playing board formed of several sections that are coupled by flexible hinges. The hinges allow the several playing board sections to be folded together for storage and transport. As another example, portable photovoltaic assemblies often include multiple photovoltaic sections coupled by hinges, such that the sections can be folded together for ease of transport and storage.
Flexible hinges rely on a stiffness differential, i.e., the hinges being less stiff than adjacent sections, to direct bending and flexing to the hinges. Accordingly, photovoltaic sections 402 may include stiffeners so that sections 402 are stiffer than hinges 404. In some other instances, packaging of photovoltaic sections 402 is inherently stiff, such that photovoltaic sections 402 are stiffer than hinges 404, even without added stiffeners. Thus, photovoltaic assembly 400 is capable of bending along flexible hinges 404 to follow underlying topology with relative ease, as shown, for example, in
Photovoltaic sections 702 include little to no appreciable stiffening elements. Thus, there is little difference in stiffness between photovoltaic sections 702 and flexible hinges 704. Such small stiffness differential between photovoltaic sections 702 and flexible hinges 704 can cause unreliable folding and unfolding. Additionally, the small stiffness differential can cause assembly 700 to not lay flat or to not follow its underlying topology very well, such as shown in
In an embodiment, an assembly includes first and second sections and a subtractive hinge coupling the first and second sections. The subtractive hinge forms at least one aperture.
In an embodiment, a photovoltaic assembly includes backing material and first, second, and third photovoltaic devices disposed on the backing material. The backing material forms at least one first aperture between the first and second photovoltaic devices to form a first subtractive hinge. The backing material further forms at least one second aperture between the second and third photovoltaic devices to form a second subtractive hinge.
In an embodiment, a method for forming a flexible photovoltaic assembly includes the following steps: (1) disposing a plurality of photovoltaic devices on a flexible backing material, such that the plurality of photovoltaic devices are divided between at least first and second sections, and (2) forming at least one aperture in the flexible backing material between the first and second sections.
Applicant has discovered that stiffness differential in flexible hinges can be achieved by removing portions of the hinge material, instead of by adding stiffening material to the coupled sections. Such technique may advantageously allow a requisite stiffness differential to be achieved without a weight and size penalty associated with adding stiffening material. In fact, removing hinge material portions typically reduces assembly size and weight, which is highly desirable in many applications. Additionally, removing portions of hinge material reduces strain in the hinge, thereby promoting ease of folding and unfolding at the hinge, as well as small hinge profile when folded. Flexible hinges with portions removed may be referred to as “subtractive hinges” to denote that hinge material has been removed. The stiffness differential achieved by subtractive hinges also helps an assembly including the hinges to follow its surface topography.
Discussed below are several examples of subtractive hinges. It should be appreciated, though, that subtractive hinges are not limited to these particular examples, but may instead encompass other configurations without departing from the scope hereof.
Sections 1104, 1106 each optionally contain one or more components (not shown), such as photovoltaic devices, communication antennas, battery packs, and/or other electronic components. For example, in some embodiments, assembly 1100 is portable photovoltaic assembly where each section 1104, 1106 includes one or more flexible photovoltaic devices, such as photovoltaic modules or submodules. Such photovoltaic devices are, for example, multiple discrete or monolithically integrated photovoltaic devices, such as thin-film or crystalline photovoltaic devices. In certain of these embodiments, some or all of the assembly includes an optical protective overlay, encapsulants, and/or adhesives, such as discussed in the examples below.
Subtractive hinge 1102 forms two apertures 1108, which represent material removed from hinge 1102. In this disclosure, specific instances of an item may be referred to by use of a numeral in parentheses (e.g., aperture 1108(1)) while numerals without parentheses refer to any such item (e.g., apertures 1108). Apertures 1108 reduce the stiffness of hinge 1102 relative to sections 1104, 1106, thereby causing adjacent sections 1104, 1106 to be stiffer than hinge 1102. Such stiffness differential promotes bending of assembly 1100 along hinge 1102. The rounded sides of rectangular-shaped apertures 1108 reduce material stress when hinge 1102 is bended. The remaining portions of hinge 1102 form hinge elements 1110, which transfer stress between sections 1104, 1106. In certain embodiments, electrical conductors, such as bus bars in the form of conductive tape, cross subtractive hinge 1102 via at least one hinge element 1110. For example, a particular embodiment includes first and second photovoltaic devices disposed in first and second sections 1104, 1106, respectively. In this embodiment, bus bars cross hinge 1102 via one or more hinge elements 1110, to electrically couple the first and second photovoltaic devices. In some embodiments, hinge 1102 couples sections 1104, 1106 in a first direction 1114, and apertures 1108 have an elongated axis 1116 perpendicular to first direction 1114.
The number, size, and/or shape of apertures 1108 in subtractive hinge 1102 may be varied without departing from the scope hereof. For example,
Similarly,
In some embodiments, the subtractive hinge forms only a single aperture. For example,
Multiple subtractive hinges may be used to couple three or more sections. For example, assembly 1100 (
The following are examples of folding apparatuses including one or more subtractive hinges, such as one or more of the subtractive hinges discussed above. It should be understood, though, that the subtractive hinges disclosed herein are not limited to use in the apparatuses of the following examples.
(A1) A folding apparatus may include a flexible backing material, one or more flexible photovoltaic sections, optical protective overlay, encapsulant/adhesives, and one or more flexible hinges between adjacent photovoltaic sections to enable folding.
(A2) In the folding apparatus denoted as (A1), the flexible backing material may include fabric and/or reinforced plastic.
(A3) In either of the folding apparatuses denoted as (A1) or (A2), the one or more flexible photovoltaic sections may be flexible photovoltaic modules.
(A4) In the folding apparatus denoted as (A3), the flexible photovoltaic modules may include monolithically integrated thin film devices.
(A5) In the folding apparatus denoted as (A4), the flexible photovoltaic modules may include an interconnected string of discrete solar cells.
(A6) In the folding apparatus denoted as (A5), the interconnected string of discrete solar cells may include flexible discrete thin film solar cells.
(A7) In the folding apparatus denoted as (A5), the interconnected string of discrete solar cells may include flexible discrete crystalline solar cells.
(A8) In any of the folding apparatuses denoted as (A1) through (A7), one or more of the photovoltaic sections may be individually packaged.
(A9) In any of the folding apparatuses denoted as (A1) through (A8), the overlay may include one or more layers of protective films.
(A10) In the folding apparatus denoted as (A9), the one or more layers of protective films may include one or more protective laminates.
(A11) In either of the folding apparatuses denoted as (A9) or (A10), the one or more layers of protective films may include one or more barriers layers, such as to protect against moisture and/or air ingress.
(A12) In any of the folding apparatuses denoted as (A9) through (A11), the one or more layers of protective films may include an outer layer including an anti-glare and/or anti-reflection coating.
(A13) In any of the folding apparatuses denoted as (A9) through (A12), the overlay may be placed at least on the photovoltaic side of the device, and the overlay may cover the entire device.
(A14) In any of the folding apparatuses denoted as (A1) through (A13), the overlay may include one or more layers of encapsulants and/or adhesives.
(A15) In the folding apparatus denoted as (A14), the encapsulants and/or adhesives may provide mechanical, electrical, and/or environmental protection to the assembly of components.
(A16) In any of the folding apparatuses denoted as (A1) through (A15), the final assembly of components may be assembled in the following sequence: (1) flexible backing material, (2) requisite adhesive/encapsulant, (3) photovoltaic circuit, (4) requisite adhesive/encapsulant, (5) barrier layer, (6) requisite adhesive/encapsulant, and (7) top protective film.
(A17) In any of the folding apparatuses denoted as (A1) through (A16), adjacent photovoltaic sections may be connected into a circuit by a flat flexible wire lead tape across the subtractive hinge.
(A18) In the folding apparatus denoted as (A17), the circuit connections between by adjacent photovoltaic sections may series and/or parallel in nature.
(A19) In any of the folding apparatuses denoted as (A1) through (A18), the assembly may provide sufficient stiffness to protect the photovoltaic sections and circuit from mechanical damage.
(A20) In any of the folding apparatuses denoted as (A1) through (A19), the entire assembly of components may be integrated into the final assembly in a single curing step.
(A21) In any of the folding apparatuses denoted as (A1) through (A20), adhesive and/or encapsulant may be cured by thermal and/or light induced energy.
(A22) In any of the folding apparatuses denoted as (A1) through (A21), hinge material may be the same or dissimilar to the flexible backing material.
(A23) In any of the folding apparatuses denoted as (A1) through (A22), folding function of the photovoltaic system may be facilitated by greater stiffness in the adjacent photovoltaic sections compared to the interconnecting hinge.
(A24) In any of the folding apparatuses denoted as (A1) through (A23), discrepancy in stiffness between photovoltaic sections and hinges may be facilitated by subtracting material in the hinge area.
(A25) In the folding apparatus denoted as (A24), the number and shape of the subtracted region of the hinge may result in two or more contiguous stress paths between adjacent photovoltaic sections.
(A26) In the folding apparatus denoted as (A25), the strength of contiguous stress paths may be sufficient for required structural integrity between photovoltaic sections.
(A27) In either of the folding apparatuses denoted as (A25) or (A26), the width and number of subtracted regions may be sufficient to determine the amount of stress required in the contiguous stress paths to generate desired hinge flexibility.
(A28) In any of the folding apparatuses denoted as (A25) through (A27), the shape of the subtracted region may be sufficient to prevent the amount of stress required in the contiguous stress paths exceeding the failure stress of the hinge material.
(A29) In any of the folding apparatuses denoted as (A25) through (A28), the height of the subtracted region may be determined by the desired thickness of the folded material in the hinge that will be enclosed.
(A30) In any of the folding apparatuses denoted as (A25) through (A29), the subtracted region may be facilitated by mechanical cutting or stamping after the product is assembled
(A31) In any of the folding apparatuses denoted as (A25) through (A30), the subtractive hinges may be created after the assembly is completed.
(A32) In any of the folding apparatuses denoted as (A25) through (A31), the bending stiffness of the subtractive hinge area may be less than the resulting stiffness of the assembled stack adjacent to the hinge to facilitate predictable flexing in this area.
(A33) In any of the folding apparatuses denoted as (A25) through (A32), the subtractive process may include mechanical cutting, stamping, and/or laser trimming.
(A34) In any of the folding apparatuses denoted as (A25) through (A33), fabric edges may be heat treated to reduce the possibility of fraying or delimitation.
Combinations of Features
Features described above as well as those claimed below may be combined in various ways without departing from the scope hereof. The following examples illustrate some possible combinations:
(B1) An assembly may include first and second sections and a subtractive hinge coupling the first and second sections. The subtractive hinge may form at least one aperture.
(B2) In the assembly denoted as (B1), the first section may include a first photovoltaic device, and the second section may include a second photovoltaic device. The first and second photovoltaic devices may each include a plurality of monolithically integrated photovoltaic cells. The assembly may further include at least one bus bar crossing the subtractive hinge to electrically couple the first and second photovoltaic devices.
(B3) In either of the assemblies denoted as (B1) or (B2), the subtractive hinge may form at least one aperture having a rounded rectangular-shape.
(B4) In either of the assemblies denoted as (B1) or (B2), the subtractive hinge may form at least one aperture having an oval-shape.
(B5) In any of the assemblies denoted as (B1) through (B4), the subtractive hinge may couple the first and second sections in a first direction, and the at least one aperture may include an aperture having an elongated axis perpendicular to the first direction.
(B6) Any of assemblies denoted as (B1) through (B5) may further include a common backing selected from the group consisting of a fabric material and a polymer material, the first and second photovoltaic devices may be disposed on the common backing, and the at least one aperture may extend through at least the common backing.
(B7) The assembly denoted as (B6) may further include first, second, third, and fourth encapsulant layers. The first photovoltaic device may be disposed between the first and second encapsulant layers, and the second photovoltaic device may be disposed between the third and fourth encapsulant layers.
(B8) The assembly denoted as (B7) may further include: (1) first, second, third, and fourth barrier layers, and (2) fifth, sixth, and seventh, encapsulant layers. The first barrier layer may be disposed between the first and fifth encapsulant layers. The second barrier layer may be disposed between the third and sixth encapsulant layers. The third barrier layer may be disposed between the second and seventh encapsulant layers. The fourth barrier layer may be disposed between the fourth and seventh encapsulant layers.
(B9) The assembly denoted as (B8) may further include a first laminate layer disposed on the seventh encapsulant layer, opposite to the first and second photovoltaic devices.
(B10) The assembly denoted as (B9) may further include an additional fabric layer disposed on the first laminate layer, opposite to the seventh encapsulant layer.
(B11) In any of the assemblies denoted as (B1) through (B10), the subtractive hinge may form a plurality of apertures.
(B12) In any of assemblies denoted as (B1) through (B11), a stiffness of the subtractive hinge may be less than a stiffness of the first section and less than a stiffness of the second section.
(C1) A method for forming a flexible photovoltaic assembly may include the following steps: (1) disposing a plurality of photovoltaic devices on a flexible backing material, such that the plurality of photovoltaic devices are divided between at least first and second sections; and (2) forming at least one aperture in the flexible backing material between the first and second sections.
(C2) The method denoted as (C1) may further include laminating the plurality of photovoltaic devices and the flexible backing material prior to the step of forming at least one aperture.
(C3) The method denoted as (C2) may further include sandwiching the plurality of photovoltaic devices between encapsulant and barrier layers prior to the step of laminating.
(C4) In any of the methods denoted as (C1) through (C3), the step of forming at least one aperture may include forming at least one aperture having a rectangular-shape with rounded sides.
(C5) In any of the methods denoted as (C1) through (C3), the step of forming at least one aperture may include forming at least one aperture having an oval-shape.
(C6) In any of the methods denoted as (C1) through (C5), the step of forming at least one aperture may include forming a plurality of apertures between the first and second sections.
Changes may be made in the above methods and systems without departing from the scope hereof. For example, although many of the assembly examples discussed above show two sections coupled a subtractive hinge, the examples can be modified to include additional sections coupled by additional subtractive hinges. Therefore, the matter contained in the above description and shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. The following claims are intended to cover generic and specific features described herein, as well as all statements of the scope of the present method and system, which, as a matter of language, might be said to fall therebetween.
This application is a divisional of U.S. patent application Ser. No. 13/783,336 filed Mar. 3, 2013, which claims benefit of priority to U.S. Provisional Patent Application Ser. No. 61/606,431 filed Mar. 4, 2012. Each of the above-mentioned applications is incorporated herein by reference.
Number | Date | Country | |
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61606431 | Mar 2012 | US |
Number | Date | Country | |
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Parent | 13783336 | Mar 2013 | US |
Child | 15673283 | US |