This present disclosure relates to solar energy production. More specifically a solar module design incorporating light management that increases power output for the same or less amount of silicon solar cells.
Solar power is accelerating as a mainstream power generation source in global markets. In order to further broaden its economic value, greater productivity of solar power system is desired by customers. Crystalline solar photovoltaic systems predominantly capture light on the front side of solar panels, on the front “face”, which can be considered “monofacial” solar panels. One method to increase power production is to harvest reflected light from the ground on the back side of the solar panels, on to special solar cells, that are designed to harvest “bifacial” energy. Bifacial solar panels have been used in the solar industry for over 10 years.
There are several key limitations on the design of bifacial solar panels that limit their utility. Initially, there is light loss through the solar panel, around the crystalline solar cells, impacted front side power. Typical crystalline modules have significant areas between the cells that are not covered by active solar cell material. Light entering these zones on a monofacial module is largely reflected, and scattered, by standard white back sheets, and partially recovered through total internal refection (TIR) onto the front sides of solar cells. On bifacial modules however, this light energy is lost because the backside of the solar panel is transparent, per design, to allow the back of the cells to receive light. While this is necessary for rear side bifaciality, front side power suffers, approximately 3-5%. This is significant loss of power.
A second limitation is caused by lower backside irradiance at the edge of the solar panel due to the partial shading of edge cells from frame profile or mounting rail elements. Frames are desirable to reduce breakage of solar panels, enable a more durable long term solar panel life, and reduce mounting system costs. However, frames have profiles that extend beyond the lower plane of the module back sheet. As a result, cell columns near the edge of the module receive less light than cells further away from the edge.
The present disclosure addresses all of these shortcomings of the known systems.
One aspect of the present disclosure describes systems and methods for increasing power output from a solar module containing bifacial solar cells by applying light management films, foils, or coatings which causes direct and total internal reflection in the module to redirect light from blank regions between the cells back to both active cell surfaces, cell front and back junctions. In particular the present disclosure is directed to shingled solar modules employing these power product improvements.
Another aspect of the present disclosure describes a bifacial solar module with enhanced power output is provided including a first transparent support layer, a first encapsulating layer, a plurality of electrically interconnected bifacial solar cells with gaps between the interconnected bifacial solar cells, a second encapsulating layer, a second transparent support layer, and one or more highly reflective films or coatings attached to the solar module at the gaps between the bifacial solar cells or an edge gap at a peripheral edge of the solar module beyond the bifacial solar cells, wherein the films or coatings redirect light impacting them such that the light is directed towards at least one of the bifacial solar cells.
In some embodiments, the first encapsulating layer and the second encapsulating layer are arranged between the first and second transparent support layers and the plurality of electrically interconnected bifacial solar cells are arranged between the first and second encapsulating layers.
In some embodiments, the one or more highly reflective films or coatings are positioned on an outer surface of at least one of the first or second transparent support layers.
In some embodiments, the one or more highly reflective films or coatings are positioned between the first transparent support layer and the first encapsulating layer, the second transparent support layer and the second encapsulating layer, or both.
In some embodiments, the one or more highly reflective films or coatings are encapsulated within the same layer of the solar cells and positioned within the gaps.
In some embodiments, the one or more highly reflective films or coatings are vertically aligned with at least one of the gaps or edge gaps of the solar module.
Another aspect of the present disclosure describes a framed bifacial solar module with enhanced power output including a frame configured to receive and secure a bifacial solar module, the bifacial module including a first and second transparent support layer, a first and second encapsulating layer arranged between the first and second transparent support layers, a plurality of electrically interconnected bifacial solar cells with gaps between the interconnected bifacial solar cells and arranged between the first and second encapsulating layers, and one or more highly reflective films or coatings attached to the solar module at the gaps between the bifacial solar cells or an edge gap at a peripheral edge of the solar module beyond the bifacial solar cells, wherein the films or coatings redirect light impacting them such that the light is directed towards at least one of the bifacial solar cells.
In some embodiments, the frame includes a side wall having a length defined between a first and second end thereof, the first end having a top support wall extending therefrom, the second end having a bottom support wall extending therefrom, and a portion along the length of the frame between the first and second ends including an intermediate support wall extending therefrom, wherein the bifacial solar module is received and secured within the frame between the top and intermediate support walls of the frame.
In some embodiments, the one or more highly reflective films or coatings are positioned on a surface of the second bottom support wall facing the solar module.
In some embodiments, the one or more highly reflective films or coatings are further positioned on an inner surface of the sidewall between the second bottom support wall and the intermediate support wall.
In some embodiments, the one or more highly reflective films or coatings are positioned at an angle relative to the solar module and extending from the sidewall near the intermediate support wall towards a free end of the second bottom support wall.
Another aspect of the present disclosure describes a solar power kit including one of the framed or frameless solar modules described herein.
The present disclosure is directed to systems and methods for increasing the energy yield of bifacial solar modules. The increase in energy yield is a result of redirecting light that would normally not be captured by the module, due to shading or gaps in solar cell coverage, back onto an active face of a solar cell.
In accordance with the present disclosure the solar cells 40 are shingled solar cells formed into strings that are separated from one another to form the gaps 45 through which light can pass. Details of forming a solar module using shingling techniques can be found in U.S. Pat. No. 9,935,221 to Zhou et al and entitled “Shingled Array Solar Cells and Method of Manufacturing Solar Modules Including the Same,” issued Apr. 3, 2018, and incorporated herein by reference.
The first transparent support layer 20 and the second transparent support layer 60 each form an outer protective layer for the cells 40 which allows light to pass therethrough to the inside of the module. The first and second transparent support layers 20, 60 also shield the contents inside the module from the physical forces of nature, such as rain, wind, snow, etc. The transparent support layers 20, 60 extend beyond the cells 40 creating an edge gap 46 between the outer edge of the module and the outermost cells 40. The transparent support layers 20, 60 are made of any suitable material including but not limited to glass or transparent polymers, such as polycarbonate, polymethylmethacrylate, polyethylene terephthalate, polypropylene, polyvinyl fluoride, polyvinylidene fluoride, fluoroethylene and vinyl ether copolymer, or other fluoropolymer.
The first encapsulation layer 30 is positioned between and separates the first transparent support layer 20 from the layer of solar cells 40. The second encapsulation layer 50 is positioned between and separates the second transparent support layer 60 from the layer of solar cells 40. The first and second encapsulation layers 30, 50 connect to the first and second transparent support layers 20, 60, respectively, on an outer surface thereof. The first and second encapsulation layers 30, 50 also connect to the layer of solar cells 40 on an inner surface thereof. The encapsulation layers 30, 50 allow light to pass therethrough to the solar cells positioned in the center thereof. The first and second encapsulant layers described herein are made of any suitable material including but not limited to, polymers or copolymers of ethylene acid, ionomers of ethylene acid copolymer, poly (ethylene vinyl acetate), poly (vinyl acetal), polyurethane, polyvinyl chloride, polyethylene, polyolefin block copolymers elastomers, poly (α-olefin-co- α,β-ethylenically unsaturated carboxylic acid ester) copolymer, silicone elastomer, epoxy resin, polyimide, fluoropolymer resins, and combinations thereof.
In the layer of solar cells 40, the edges of any two neighboring solar cells 40 are spaced apart providing a gap 45 therebetween. The gap 45 has a substantially uniform width (taking into account manufacturing, material, and environmental tolerances) between the two adjacent cells 40 of about 0.5 mm to about 50 mm. In some embodiments, the gap 45 has a substantially uniform width of about 1 mm to about 25 mm. In some embodiments, the gap 45 has a substantially uniform width of about 2 mm to about 5 mm.
The outer edges of the solar module and the outside edge of the outermost cells closest to the outer edge of the solar module create edge gaps 46 having a substantially uniform width (taking into account manufacturing, material, and environmental tolerances) between about 0.5 mm to about 50 mm. In some embodiments, the edge gap 46 has a substantially uniform width of about 1 mm to about 25 mm. In some embodiments, the gap 45 has a substantially uniform width of about 2 mm to about 5 mm. In some embodiments, the edge gap 46 has a width smaller than a width of the gap 45. In some embodiments, the edge gap 46 has a width larger than a width of the gap 45.
The cells 40, although shown separated by the gap 45, may still be electrically connected in parallel or series using any suitable method. In one embodiment, each cell 40 is connected in series to the next cell 40 with a single positive and negative terminal for the solar panel module 100. Alternatively, in some embodiments, bus bars may be employed to allow for connection of some or all of the cells 40 in parallel. The electrical connections may depend on the vehicle, its battery charging voltages, and the minimization of shadowing effects.
In some embodiments, at least the first and intermediate support walls 106, 108 are spaced apart from each other a distance generally equal to a thickness of the solar module 200. In some embodiments, each of the support walls 106, 107, 108 are each spaced apart from each other a distance generally equal to a thickness of the solar module 200.
In some embodiments, the first and intermediate support walls 106, 108 have a length smaller than a length of the second support wall 107. In some embodiments, the first and intermediate support walls 106, 108 have a length generally equal to the edge gap 146. In some embodiments, the lower support wall 107 has a length greater than the edge gap 146.
The highly reflective films or coatings can be formed using any suitable reflective material including, but not limited to, reflective polymers such as polyethylene terephthalate (PET), triacetate cellulose (TAC), and ethylene tetrafluoroethylene (ETFE), reflective metals such as aluminum, silver, gold, copper, palladium, platinum, or alloys, ceramic materials, paint, or materials formed in the prism shaped, or combinations thereof.
In general, regardless of HRF or HRC, if the highly reflective material is placed on the underside of the solar module, as depicted at least in part of
In the embodiments where the HRF or HRC is on substantially the same plane as the solar cells, as depicted at least in part of
In embodiments where the HRF or HRC is above the front side of the solar cells (the side directly facing the sun), as depicted at least in part of
The modules 400a-g each include a plurality of strips of the HRF or HRC 470, first and second transparent support layers 420, 460, first and second encapsulation layers 430, 450, and one or more bifacial solar cells 440 spaced apart horizontally from each other by gap 445. The solar cells 440 are positioned between the first and second encapsulation layers 430, 450. The encapsulation layers 430, 450 positioned between the first and second transparent support layers 420, 460. The plurality of strips of the HRF or HRC 470 are positioned intermittently across a width of the solar module 400a-g and along various layers of the modules 400a-g. In some embodiments, each strip of the HRF or HRC 470 is vertically aligned with the gaps 445 between the solar cells 440, such that each strip of HRF or HRC 470 extends a length generally equal to the width of the gaps 445 between the solar cells 440.
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In some embodiments, the plurality of strips of HRF or HRC may be positioned all within the same layer of the solar module (see, e.g.,
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In some embodiments, the plurality of strips of HRF or HRC may be positioned all within the same layer of the framed bifacial solar module (see, e.g.,
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In addition to the several different embodiments individually depicted in the present Figures, it is further envisioned that in some embodiments, the solar modules described herein may position the HRF or HRC in various combinations of the Figures. For example, in some embodiments, the solar modules described herein may include HRF or HRC which is vertically aligned with the gap between the cells (see, e.g.,
Although embodiments have been described in detail with reference to the accompanying drawings for illustration and description, it is to be understood that the inventive processes and apparatus are not to be construed as limited thereby. It will be apparent to those of ordinary skill in the art that various modifications to the foregoing embodiments may be made without departing from the scope of the disclosure.
Number | Date | Country | |
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62677916 | May 2018 | US |