Light management system for optimizing the performance of bifacial solar modules

Abstract

The present invention discloses a bifacial solar module with enhanced power output, comprising: first and second transparent support layers; a plurality of electrically interconnected bifacial solar cells arranged between the transparent support layers, with a gap between one or more of the interconnected solar cells and the edges of the first and second transparent support layers, the bifacial solar cells having a first side directly exposed to solar radiation and a second side opposite the first side. The bifacial solar module further comprises one or more microstructured reflective strips positioned to coincide with the gap and attached to a surface of the second support layer, so that light passing through the second support layer is reflected back to the second support layer at a variety of angles, so that light reflected from the strips is absorbed by the first or second side of the bifacial solar cells.

Description

Technical Field

[0001] The present invention relates to solar energy generation. More particularly, the present invention relates to solar module designs that incorporate light management to increase the power output of the same or less number of silicon solar cells. Background Art

[0002] Solar power generation is accelerating to become a mainstream power generation source in the global market. In order to further expand its economic value, customers expect higher productivity from solar power generation systems. Crystalline solar photovoltaic systems mainly capture light on the front side of the solar panel (on the positive "face"), which can be considered a "single-sided" solar panel. One way to increase power generation is to collect light reflected from the ground on the back side of the solar panel to special solar cells designed to collect "two-sided" energy. Two-sided solar panels have been used in the solar industry for more than 10 years.

[0003] There are several key limitations to the design of two-sided solar panels that limit their practicality. First, there is light loss through the solar panel, around the crystalline solar cells, which affects the front-side power. Typical crystalline modules have a large area between the cells that is not covered by active solar cell material. Light entering these areas on a single-sided module will be reflected and scattered to a large extent by a standard white backplane, and partially recovered by total internal reflection (TIR) ​​on the front side of the solar cell. However, on a two-sided module, this light energy is lost because, by design, the back side of the solar panel is transparent to allow the back of the cell to receive light. Although this is necessary for the back-side bifaciality, the front-side power is affected, about 3 to 5%. This is a significant power loss.

[0004] The second limitation is caused by lower backside irradiance at the edge of the solar panel due to partial shading of the edge cells by the frame profile or mounting rail elements. The frame is needed to reduce breakage of the solar panel, achieve a more durable long-term solar panel life, and reduce installation system costs. However, the profile of the frame extends beyond the lower plane of the module backsheet. As a result, the cell columns near the edge of the module receive less light than the cells farther away from the edge.

[0005] The third limitation is lower backside irradiance at the center of the solar panel due to reduced availability of reflected light on the center cell rows, affecting the center cell rows, which can be attributed to the geometry of incoming incident reflected light offset from the center cell rows and / or can be attributed to the rear structure tubes under the center of the module, which reduce the total light available to those center cell rows.

[0006] In addition to the above, tracking systems are often used with solar modules to reduce cosine losses that occur over the course of a day due to angular displacement of the panels with the incident sun angle. These systems consist of either one-dimensional or two-dimensional systems (single-axis or dual-axis, respectively) that direct the panels orthogonally to the incoming solar rays. In either case, tracking imposes limitations on the system output per land area because self-shading requires that panels be placed in arrays with dead spots where light is not directly incident on the surrounding panels. To compensate for some of these losses, bifacial solar modules can be used to recapture light that falls between the system rows by diffusely collecting ground-reflected light onto the back side of the panels for further power generation. However, diffuse reflections from surrounding ground areas are far from optimal due to absorption and the randomly directed light absorbed away from the solar panel. This power reduction can offset the power enhancement available from bifacial solar modules.

[0007] The present invention solves all of these disadvantages of known systems. Summary of the invention

[0008] Bifacial solar panel arrays offer the opportunity to enhance the collection of solar energy in these dead spots using specific reflective surfaces. One aspect of the invention describes systems and methods for increasing the power output from a solar module containing bifacial solar cells by applying a light management film to the exterior (preferably the backside) of the module that causes direct and total internal reflection in the module to redirect light from the empty space between cells back to the junction of the two active cell surfaces, the front and back sides of the cell. Because a large area can be redirected, it is also advantageous to increase the gap between cells or use partial cells to create a concentration greater than 1 for the module.

[0009] One aspect of the present invention relates to a bifacial solar module with enhanced power output, comprising: first and second transparent support layers; a plurality of electrically interconnected bifacial solar cells arranged between the first and second transparent support layers, with a gap between one or more of the interconnected solar cells and edges of the first and second transparent support layers, the bifacial solar cells having a first side directly exposed to solar radiation and a second side opposite the first side; and one or more microstructured reflective strips positioned to coincide with the gaps and attached to a surface of the second support layer so that light passing through the second support layer is reflected back into the second support layer at a variety of angles so that light reflected from the strips is absorbed by the first or second side of the bifacial solar cells.

[0010] The microstructured reflective tape may be adhered to the second transparent support layer using a UV curable adhesive material or using an acrylic material. The adhesive may be pre-adhered to the microstructured reflective tape before being applied to the second transparent support layer.

[0011] According to one aspect of the invention, the microstructured reflective tape comprises prisms positioned against the second transparent supporting layer.Alternatively, the microstructured reflective tape may comprise prisms positioned on the back side of the tape away from the surface of the second transparent supporting layer.

[0012] Regarding one aspect, the microstructured reflective tape reflects light directly into the second side of the bifacial cell. The microstructured reflective tape may also reflect light into the second side of the bifacial solar cell and reflect light downward onto the front surface of the bifacial cell at an angle sufficient to be totally internally reflected from the first transparent supporting layer. In one aspect of the invention, at least a portion of the light totally internally reflected from the first transparent supporting layer is further totally internally reflected from the second transparent supporting layer and reflected onto the second side of the bifacial solar cell.

[0013] According to the present invention, the microstructured reflective tape comprises prisms having a plurality of prism angles. The plurality of prism angles reflect light at different angles to strike the first or second side of the bifacial solar cell. In addition, the gap occupies the perimeter of the bifacial cell, and the microstructured reflective tape comprises prism angles configured to maximize light from the perimeter gap.

[0014] In one aspect of the invention, the gap is 1 to 300 mm wide across the centerline of the first and second transparent support layers, thereby dividing the plurality of bifacial cells into two electrically interconnected regions. The bifacial solar cells can be cut into less than a whole cell and can be electrically integrated to form two groups of serially interconnected cells, each of which is connected in parallel within the same module.

[0015] According to the present invention, the first and second transparent support layers are glass or polymer. In addition, the microstructured reflective tape includes prisms arranged in two or more zones across the tape. In addition, the prism shapes within each zone may be substantially the same, and at least two zones may have prisms formed with different angles for reflecting the solar radiation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Depicts a reflective band according to the present invention;

[0017] Figure 2A and 2B Depicting a tape having an adhesive applied to one side of the tape according to the present invention. Figure 1 Reflective bands;

[0018] Figure 3 Describe the gap in the center of the solar module and the Figure 1 The reflective band reflects solar radiation;

[0019] Figures 4A to 4C Depict the reflective bands at the edges and the gaps between cells on a solar module;

[0020] Figure 5 Depicting the reflection bands of the microstructures of the present invention having regions of different reflection angles;

[0021] Figures 6A to 6D depicts a plurality of solar modules according to the present invention;

[0022] Figures 7A to 7C depicts a plurality of solar modules according to the present invention;

[0023] Figure 8 depicts a solar module according to another aspect of the invention;

[0024] Figures 9A to 9F Describes solar modules and assemblies having reflective assemblies of the present invention;

[0025] Fig.10 Depicts a linear tracking solar array with dead spots between rows and random light collection;

[0026] Figures 11A to 11F Depicting a flexible reflective arrangement according to the present invention;

[0027] Fig.12 Depicting a multi-vertex flexible reflection arrangement according to the present invention;

[0028] Fig.13A depicts a full parabolic system for reflecting light to the back side of a two-sided array in accordance with the present invention in a first orientation;

[0029] Fig. 13B depicts a full parabolic system in a second orientation for reflecting light to the back side of a two-sided array in accordance with the present invention;

[0030] Fig.14A depicting a two-sided array of ground-based static reflectors in a first orientation according to the present invention; and

[0031] Fig. 14B A two-sided array of ground-based static reflectors in a second orientation is depicted in accordance with the present invention. DETAILED DESCRIPTION

[0032] The present invention relates to systems and methods for increasing the energy yield of bifacial solar modules. According to certain aspects of the invention, bifacial solar modules are used with single-axis solar tracker devices, however, other applications are contemplated within the scope of the invention, including fixed-position mounted dual-axis solar trackers and others.

[0033] Figure 1A microstructured reflective tape 10 according to the present invention is shown. The reflective tape 10 comprises a polymer carrier film 12 and UV prisms 14 formed on one surface of the film. In at least one embodiment of the present invention, the empty space between the solar cells on both sides of a solar module is covered by one or more of these microstructured reflective tapes 10 on the back surface of the module. The reflective tape 10 is designed to transmit light back to the active surface of the solar cell by direct and total internal reflection, as described in detail with respect to FIG. Figure 3 The surface of the prism 14 may be coated with a reflective material to provide efficient reflection of incident light. Figure 2A and 2B , the film 10 may have an optically clear adhesive 16 applied to the polymer film 12 or prism 14 to adhere to the underside of the solar module. Although applying the adhesive to the prism can provide a low-profile and less likely to sticky solution, special care must be taken when applying the adhesive to the reflective tape 10 to ensure that bubbles are not formed and there is enough adhesive to ensure good adhesion to the solar module. In addition, in this embodiment, the polymer film is not exposed to direct solar radiation, which can provide some durability benefits. Alternatively, applying the adhesive to the polymer film 14 can provide some manufacturing benefits at the potential cost of reduced reflectivity, which is due to the need for the polymer film to be translucent and reliable even when exposed to solar radiation. The optically clear adhesive 16 and the polymer film 12 can have a refractive index that is almost equal to the transparent or translucent back sheet of the solar module. Alternatively, other refractive indices can be used for the adhesive or polymer film to provide additional optical effects. The adhesive 16 can be UV curable and can further be acrylic.

[0034] In About Figure 2A In another embodiment of the embodiment, the polymer film 12 can be removed from the prism 14 after the adhesive 16 is adhered to the solar module. In addition, in general, the optically clear adhesive should fill between 90% and 100% of the air gap between the prism 14 or polymer film 12 and the back sheet of the solar module 20. The prism 14 preferably has a plurality of coplanar prisms having a bevel angle between 1 and 45 degrees and a draft angle between 45 and 90 degrees and a height between 1 and 1000 microns. In addition, the prism 14 can be coated with a highly reflective material. In addition, the microstructured reflective band prism 14 can be formed using a UV curable polymer or hot embossing. In addition, the microstructured reflective band prism 14 can be formed on a polymer base tape 12 that is separated from the prism 14 and removed from the prism 14 after being adhered to the back side of the glass 24 ( Figure 3 ).

[0035] Figure 3Depicting the use of a reflective tape applied to the back surface of a solar module 20. The solar module 20 includes two solar cells 22 sandwiched between two glass sheets 24 and embedded in a backing material 26 such as ethylene vinyl acetate (EVA). Sunlight, graphically shown as lines 28, strikes the solar module 20 and passes through the glass 24 and EVA 26. Without the reflective tape 10, this sunlight would pass completely through the module 20 and a substantial portion of its energy would be lost, heating the air on the opposite side of the solar module.

[0036] exist Figure 3 In the embodiment of FIG. 1 , sunlight 28 strikes the reflective tape 10 and is redirected back toward the solar cell 22. Some of this reflected light is reflected directly back toward the underside of the solar cell 22 and absorbed there. Other components of the reflected light return to the glass 24 and are reflected back again toward the front side of the solar cell 22 by total internal reflection (TIR) ​​or actually undergo multiple reflections (a first pass through the reflective tape 10, a second pass through the TIR of the glass 24, and then a third pass through the reflective tape 10) before achieving a reflection angle that strikes the solar cell 22 and is absorbed. All of these paths can be seen in FIG. Figure 3 The reflection path is depicted as a dotted line.

[0037] One advantage of applying the reflective film to the exterior of the module is that the reflective film 10 avoids the high heat of the lamination process used to construct the solar module itself. This allows for simple incorporation into the module process with little impact on the module production line itself, and even allows for aftermarket retrofitting of existing solar modules to achieve some, if not all, of the increases in energy production contemplated herein.

[0038] Figure 4A Another application of reflective tape 10 is shown along the gap at the edge of a solar module 20. The solar module 20 is secured within an aluminum frame 30 common to solar modules. The reflective tape 10 positioned at the gap can reflect to the edge cells of the solar module 20, which in some examples may be shaded by the frame 30. As is well known, shading reduces overall module output. The reflective tape 1 at the edge can redirect sunlight 28 that would normally be lost in the back side (or front side) of the solar module to help eliminate shadow losses due to the frame and thus increase overall solar module output. Figure 4B A similar cross section of a solar module is depicted with a frame 30 that may create a more extreme shading effect on the back side of solar module 20 . Figure 4C A front view of a solar module 20 is depicted with a reflective tape 10 formed between the outermost cells 22 and the frame 30 around the gap along the edge of the solar module 20 .

[0039] Figure 5Another aspect of the present invention is described. Specifically, Figure 5 An arrangement of prisms 14 on a reflective tape 10 comprising different zones is shown, wherein each zone has different properties for the prisms 14 formed therein. As shown, all prisms have the same basic shape (e.g., a triangle) and have a common height (e.g., 10 mm). However, the angles of the prisms 14 may vary from zone to zone. By having the prisms 14 have the same properties within a zone, manufacturing costs may be reduced by reducing processing requirements. In addition, each zone may be designed to perform light redirection independently of other zones. For example, a zone positioned on the edge of the reflective tape 10 may consist of one prism with one facet angled to redirect light directly onto the back of one of the two-sided cells, and another facet may direct light to TIR from the front glass surface to the front surface of the other two-sided cell or TIR again from the back surface of the back glass back onto the back of the other two-sided cell. Combinations of these zones may be used to fully recover light lost due to gaps between cells, frame edges, j-boxes, module center regions, and other features of solar modules.

[0040] Fig. 6A C depicts a solar module with a gap intentionally added to the center of the module, dividing it in half. This gap may be formed in a single module as depicted here or may be the result of using two smaller modules. Typically, the gap is aligned with the module's support structure, which, like the frame, creates shading to the back side of the module, resulting in shading and potential power output loss. Figure 6B By adding gaps and reflective strips 10 in the center region as depicted in FIG, sunlight is reflected into the solar cells 22 of the solar module 20. This results in an increase in overall power output since the back side of the solar cell 22 potentially receives greater solar energy at a significantly lower cost.

[0041] Figure 6B and 6C Another aspect of the invention is depicted using half a battery. That is, Fig. 6A The standard solar cell 22 depicted in FIG. 2 can be cut in half. As is known, each solar cell outputs the same voltage regardless of its size. The current output is a function of the surface area of ​​the solar cell and the amount of solar radiation it can absorb. Figure 6B and 6C As depicted in Figure 2, even if the surface area of ​​the solar cell is now cut in half, the overall output power increases by about the same amount as Fig. 6A In addition, by adjusting the spacing and utilizing more reflection bands, Figure 6C The output of solar modules in the Figure 6B Output, adding more solar cells is the main cost in the solar module manufacturing process.

[0042] Figure 5 An example of combining individual ribbons into lossy regions to recover light from several lossy regions is shown. This can result in maximum power output compared to modules that do not include ribbon enhancement. In addition, it is expected that Fig.6D The solar module will have even better performance than the reflective strip 10 in both vertical and horizontal directions. Figure 6C Greater output, thereby further maximizing the reflective potential output. Figures 7A to 7C Describes something similar to Figures 6A to 6D An arrangement of reflective tape 10 is used between cells and in the gaps between cells and the frame of the solar module.

[0043] Generally speaking, after calculation, for example Fig. 6A A monofacial solar module of the type depicted in the diagram will have an output of about 360W. By making the same bifacial module, an increase from 30W to 390W can be expected. Figure 7B The full cell bifacial module with the reflective bands depicted in the figure can be further increased to about 400W. Figure 6C and 6D Solar modules configured with can be expected to have outputs of 430W and 450W respectively.

[0044] As mentioned above, Figures 6B to 6D Using cells formed by cutting whole cells. Cutting cells to reduce current and resistance losses is becoming more and more popular. Modules built from half cells are used to create Figures 6A to 6D The use of cut cells allows for the intentional use of the gaps between cells to increase the ratio of reflective tape to cell. Since the cost of reflective tape 10 is much lower than that of cells, there is a great potential to reduce the overall cost of solar energy. At a minimum, the combination of half cells with a center gap, edge tape, and recovery from other cell gaps has the potential to produce the most powerful modules available at a significantly reduced cost, as described above with reference to Fig.6D Mention.

[0045] In addition to the foregoing, the present invention contemplates placing reflective strips or other triangular reflective structures directly on the torque tube of a solar tracker (e.g., Fig.10 As seen in Figures 6A to 6DAs mentioned in , the center of a bifacial solar module is typically not covered by a solar cell, placing a triangular shaped or reflective prism strip 10 directly on the torque tube (about 2 inches from the solar module) can effectively reflect most of the light that passes through the solar module and is not captured, back to the two sides of the solar cell. Some portion will be reflected to the back side of the solar cell, and some will be reflected to the front glass and captured via TIR. In addition, some sunlight can be reflected to an adjacent solar module on a separate tracker (i.e., reflected both east and west from the triangular reflector).

[0046] Another variation of this can be seen in Figure 8 In which the prisms 14 on the reflective tape may be arranged with appropriate side angles between 44.5 degrees and 1 degree (see Figure 5 ) to allow collection from over a quarter of the cell, depending on the glass thickness. This allows the module 20 to be constructed using quartered cells, with the gaps between cells large enough to produce a net concentration greater than 1. For example, cells with dimensions of 39mm x 156mm arranged with a gap of 39mm between cells (perhaps in a linear arrangement) with a film 39mm wide to fill the gap can produce a module with a ratio of 1.8 or more, depending on the optical efficiency of the cells. This can produce solar modules with lower cost and sufficient power to reduce the cost per watt of the module by 10% or more.

[0047] In one embodiment, the width of the cell is approximately the same as the reflective tape 10, this ratio of tape 10 to cell 22 width produces a concentration of light onto the cell of between 1.1 to 5X depending on the width. The cell can be cut along two dimensions with the tape extending in both width and length to further increase the concentration.

[0048] Another aspect of the present invention refers to Figures 9A to 9F A solar module 20 is seen and referred to wherein reflective properties are built into the solar module frame. Fig. 9A Depicted is a front perspective view of a solar module 20 having a frame 30 and a plurality of solar cells 22. Although shown here as full cells, half, quarter, third, fifth, sixth, and other sizes may be employed without departing from the scope of the present invention. Fig. 9B Depicted is the back side of solar module 20. Support 32 can be seen extending between the two sides of frame 30 along the midline of solar module 20. As will be explained in more detail below, support 32 functions similarly to reflective strip 10 described elsewhere herein.

[0049] Fig. 9C A cross-sectional view of a solar module 20, and in particular, a cross-sectional view of a frame 30 is depicted. Fig. 9C30, the protrusion 34 extends from the frame. The protrusion 34 can be polished aluminum or other material forming the frame 30. The protrusion 34 extends from the sidewall of the frame 30 at an angle to the sidewall. This angle of the protrusion relative to the sidewall can be between 1 and 80 degrees, between 5 and 75 degrees, between 10 and 70 degrees, between 15 and 65 degrees, between 20 and 60 degrees, between 25 and 55 degrees, between 30 and 50 degrees, between 35 and 45 degrees, and between 40 and 45 degrees.

[0050] In one embodiment, the protrusion extends from the frame at an angle of about 45 degrees. As with the reflective tape 10 described above, sunlight passes through the gap 35 between the solar cell 22 and the frame 30 and strikes the protrusion. The sunlight is then reflected onto the underside of the solar cell 22 or back into the top glass to be reflected onto the front surface of the solar cell 22 by TIR. As should be appreciated, the reflective tape 10 can also be used in other gaps in conjunction with the protrusion 34.

[0051] Fig.9D A cross-sectional view of a support 32 extending from an interior surface of the frame 30 is depicted. The support 32 has a generally trapezoidal shape with a flat top surface 36 and two side walls 38. Both the top surface 36 and the side walls 38 serve to reflect sunlight passing through a gap 37 formed in the center of the solar module 20 onto the solar cell 22. The support 32 performs two functions, first, the flat top surface 36 and the two angled side walls 38 serve to reflect light back into the bottom surface of the solar cell 22 or upward through the glass of the solar module 20 to be reflected onto the top surface of the solar cell 22 due to TIR. Second, the support 32 provides additional rigidity to the solar module 20. This additional rigidity is becoming necessary as solar module manufacturers reduce the size and rigidity of the frame 30 of the solar module 20 to reduce costs. Furthermore, if desired, this support 32 can be retrofitted into an existing solar module to provide a reflective function.

[0052] Fig.9E and 9F A frame 30 is depicted having a protrusion 32 and a support 34 in its generally trapezoidal cross-section. The slanted sides of the support may have an angular orientation similar to that described above with respect to the protrusion 32. As mentioned above, the protrusion 32 and support 34 may be aluminum, and may be polished or painted to enhance its reflectivity.

[0053] In this article Figures 10 to 14B Another aspect of the present invention is described. Fig.10Depicted are two single-axis solar module tracking arrays 100. The axis of the tracking system (about which the solar module 20 rotates) is generally aligned on the North / South (polar axis) as the solar module 20 rotates about the axis through a fixed range of angles during the course of a day. In the case of bifacial solar modules, diffuse radiation from the surrounding area provides additional power through reflections off ground features. Due to the random nature of the reflections, only a small fraction of the reflected light is transmitted back to the panel for conversion, and most of the sunlight hits the so-called "dead zone" that does not transmit light back to the solar module.

[0054] Fig.11A Figures 1 to 2 depict two embodiments of the present invention showing a metallized mirror film 102 having a thickness between 5 and 100 microns. In one example, the film 102 has a thickness of 50 microns. The film 102 can be made of a material commonly known under the trade name The solar tracker 100 is made of biaxially oriented polyethylene terephthalate (BoPET) and is arranged with a moving apex that can change the slope and shape of the metallization or mirror surface to provide maximum reflection to the bifacial cells 22 of the solar module 20 as the solar module 20 tracks the sun throughout the day. Low-cost materials and support structures can be mechanically or electrically connected to the solar tracker 100 to synchronize the mirror shape with the incident angle of sunlight.

[0055] Figures 11A to 11C Depicts a system with a movable lower vertex 104. In this case, the membrane 102 is securely attached to the tracker 100. By moving the position of the lower vertex as the incident angle of the sunlight changes, the reflection of the sunlight also changes. Fig.11A middle( Fig.11A The reflected light is directed to the leftmost tracker 100 and the back side of the two-sided solar module 20 associated with it. Fig. 11B The movement of the lower vertex 104 in the opposite direction of the sun's movement changes the reflection angle of the sunlight and causes both trackers 100 to receive reflected light on the underside of the solar module 20. Fig. 11C In FIG. 1 , the solar tracker 100 reaches a noon position, where the sun is directly overhead. Therefore, the reflected sunlight is shared equally between the two solar modules 20 of the two trackers 100.

[0056] exist Figures 11D to 11F In the various embodiments depicted in FIG. 1 , lower vertex 104 is held in place and does not move as solar panel 20 is rotated by tracker 100. Instead, upper vertex 106, which are maintained at a constant distance from each other, are moved to ensure that solar energy is reflected into the back side of the bifacial solar module. Fig.11F, the reflection is reflected equally into both trackers 100, and in particular, into their solar modules 20. Alternatively, both upper apex 106 and lower apex 104 may be movable. In yet another embodiment, where the upper and lower apex are movable, the distance between them may be variable. In some embodiments, tension rollers (not shown) or other means are used to feed and retract the film when necessary to maintain constant tension and mirror shape throughout the daily cycle.

[0057] Fig.12 is another embodiment of the present invention in which additional upper vertices 106 and additional lower vertices 104 are used to span larger distances. Generally, for a solar tracker tracking + / -50 degrees, one set of vertices is sufficient, however, in some examples with irregular spacing or when larger tracking angles are used, more than one set of vertices may be used, such as Fig.12 In the Fig.12 Variations regarding which vertices 104 and 106 are movable or fixed as described above may also be employed in the multiple vertex case depicted in FIG.

[0058] 13-14 depict various mechanisms to enhance the yield of a solar array that employs reflective materials to redirect solar energy back toward the solar panels. The mechanisms are positioned on either side of the tracker 100 depending on the orientation of the solar modules 20 on the tracker 100.

[0059] exist Fig.13A and 13B In the embodiment of FIG. 1 , each tracker 100 is equipped with at least one parabolic reflector 110. The reflector 110 redirects sunlight into the back side of the solar module 20 supported by the tracker 100. Figures 13A to 13B As the tracker reaches the midday position, Fig. 13B In the embodiment of the present invention, reflectors 110 are positioned on either side of tracker 100 so that both the left and right sides of solar module 20 receive reflected sunlight. In contrast, in a more angular position, reflectors 100 may be placed in a more offset position, where only one of reflectors 110 reflects sunlight to the entire solar module 20.

[0060] exist Fig.14A and 14B In the embodiment, one or more ground mounted parabolic reflectors 112 may be used. Figures 14A to 14B As can be seen in the progression of FIG. 1 , when in angular conditions, the reflector 112 redirects sunlight onto the backside of a single tracker 100 and solar module 20. However, as the sun approaches its zenith, the parabolic reflector 112 redirects sunlight onto both the parabolic tracker 100 and its corresponding solar module 20.

[0061] exist Fig. 14B In FIG. 1 , another embodiment is shown whereby the central portion of the parabolic reflector 112 may be replaced by a prismatic structure 114, although it may have different dimensions, similar to the above description of Figure 1 The prismatic structures described are no different. The prismatic structures 114 are mounted on the ground and are generally fixed to the ground between the two trackers 100. In fact, it is contemplated that the parabolic reflector 112 may be completely replaced by a series of prismatic structures 114 placed on either side of the solar tracker. These prismatic structures may be formed from nearly any inexpensive base material, including wood, concrete, metal, plastic, etc. and coated with a layer of reflective material, such as the BoPET described above.

[0062] In the embodiments of FIGS. 13-14 , a white fabric may be employed. The white fabric causes reflection of light from the surrounding solar panels and reflects it upward back to the solar module. In some embodiments, the fabric is angled. Similarly, in some embodiments, it may be a metal coated or uncoated fabric or low cost plastic formed into triangular angles that is placed between the solar trackers. For example, the ground mounted prismatic structure 114 may be replaced by a simple white fabric. While not an ideal solution, a portion of the reflected light will reach the solar module 20 and this increases the power output.

[0063] In yet another embodiment, a single or multiple angled devices are placed between solar trackers 100 and can be used to reflect light back toward solar modules 20. In one example, the angled devices have a substantially triangular shape. The top of the triangle is about 1 foot apart from the solar module 20 and has a slope toward the center of the panel with a slope of about 15 degrees (possibly between 5 and 20 degrees). Light that strikes this front side is reflected into the solar module 20. On the back side of the triangular element, there can be a slope of about 65 degrees, which then reflects light that strikes the back side of the triangular device into the solar panel of the adjacent tracker.

[0064] Although the embodiments have been described in detail with reference to the accompanying drawings for illustration and description, it should be understood that the inventive process and apparatus should not be interpreted as being limited thereto. It should be apparent to those skilled in the art that various modifications may be made to the foregoing embodiments without departing from the scope of the invention.

Claims

1. A bifacial solar module with enhanced power output, comprising: First and second transparent support layers; a plurality of electrically interconnected bifacial solar cells arranged between the first and second transparent support layers with a gap between one or more of the plurality of electrically interconnected bifacial solar cells and edges of the first and second transparent support layers, the plurality of electrically interconnected bifacial solar cells having a first side directly exposed to solar radiation and a second side opposite to the first side; one or more microstructured reflective tapes positioned to coincide with the gaps and attached to a surface of the second transparent supporting layer such that light passing through the second transparent supporting layer is reflected into the second transparent supporting layer at a variety of angles such that light reflected from the one or more microstructured reflective tapes is absorbed by the first or second side of the plurality of electrically interconnected bifacial solar cells, wherein the one or more microstructured reflective strips include prisms having a triangular profile defining a base and first and second side surfaces arranged in two or more zones across the width of the one or more microstructured reflective strips, Characterized in that the first side surface and the second side surface of the prism in the first zone among the two or more zones define an internal angle relative to the base, and the internal angle is different from the internal angle defined by the first side surface and the second side surface of the prism in the second zone among the two or more zones relative to the base.

2. The bifacial solar module of claim 1, wherein the one or more microstructured reflective tapes are adhered to the second transparent support layer with a UV curable adhesive material.

3. The bifacial solar module of claim 1, wherein the one or more microstructured reflective tapes are adhered to the second transparent support layer with an acrylic material.

4. The bifacial solar module of claim 1 further comprising an adhesive, wherein the adhesive is pre-adhered to the microstructured reflective tape prior to being applied to the second transparent support layer.

5. The bifacial solar module of claim 1, wherein the one or more microstructured reflective strips comprise prisms positioned against the second transparent support layer.

6. The bifacial solar module of claim 1, wherein the one or more microstructured reflective tapes comprise prisms positioned on a rear side of the one or more microstructured reflective tapes away from the surface of the second transparent supporting layer.

7. The bifacial solar module of claim 1, wherein the one or more microstructured reflective strips reflect light directly into the second side of the plurality of electrically interconnected bifacial solar cells.

8. The bifacial solar module of claim 1 , wherein the one or more microstructured reflective strips reflect light into the second side of the plurality of electrically interconnected bifacial solar cells and reflect light downward onto the front surfaces of the plurality of electrically interconnected bifacial solar cells at an angle sufficient to be completely internally reflected from the first transparent support layer.

9. The bifacial solar module of claim 8, wherein at least a portion of the light totally internally reflected from the first transparent supporting layer is further totally internally reflected from the second transparent supporting layer and reflected onto the second side of the plurality of electrically interconnected bifacial solar cells.

10. The bifacial solar module of any preceding claim, wherein a plurality of prism interior corners reflect light at different angles to impinge on the first or second side of the plurality of electrically interconnected bifacial solar cells.

11. The bifacial solar module of claim 10, wherein the gap occupies a perimeter of the plurality of electrically interconnected bifacial solar cells, and the one or more microstructured reflective strips include the plurality of prism internal angles configured to maximize light from the gap at the perimeter.

12. The bifacial solar module of claim 1, wherein the gap is 1 to 300 mm wide across the centerline of the first and second transparent support layers, thereby dividing the plurality of electrically interconnected bifacial solar cells into two electrically interconnected regions.

13. The bifacial solar module of claim 1, wherein the plurality of electrically interconnected bifacial solar cells are cut into less than whole cells.

14. The bifacial solar module of claim 1, wherein the plurality of electrically interconnected bifacial solar cells are cut into half cells and electrically integrated to form series-interconnected groups of two half cells, each of the two series-interconnected groups being connected in parallel within the same module.

15. The bifacial solar module of claim 1, wherein the first and second transparent support layers are glass or polymer.

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