Concentrated Photovoltaic System Modules Using III-V Semiconductor Solar Cells

A SOLAR CELL RECEIVER (100) FOR USE IN A SOLAR CONCENTRATION SYSTEM (102) CONCENTRATING SOLAR ENERGY IN A SOLAR CELL TO CONVERT SOLAR ENERGY IN ELECTRICITY. THE SOLAR CELL RECEIVER (100) MAY INCLUDE A SOLAR CELL (102) MOUNTED ON A SUPPORT AND WITH ONE OR MORE LAYERS OF COMPOUND SEMICONDUCTOR lll-V. AN OPTICAL ELEMENT (106) CAN BE POSITIONED ON THE SOLAR CELL (102) AND HAVE AN OPTICAL CHANNEL WITH

An inlet that is turned away from the solar cell and an outlet that is turned toward the solar cell. A STRUCTURE (170) CAN BE POSITIONED ON THE BRACKET AND EXTEND AROUND THE SOLAR CELL (102) WITH THE STRUCTURE (170) HAS AN INNER SIDE extending above the BRACKET AND IS FACING TO THE OPTICAL ELEMENT (106) . An encapsulant (160) may be positioned on the support and contained between the optical element (106) and the structure (170). The encapsulant (160) may have increased heights at points of contact with the optical element (106) and the structure (170) and a reduced height between the points of contact of the optical element (106) and the structure (170). THE SOLAR CELL RECEIVER (100) CAN BE USED ON A SOLAR CELL MODULE (200).

RESUME

A SOLAR CELL RECEIVER FOR USE IN A CONCENTRATED PHOTOVOLT SYSTEM USING III-V SEMICONDUCTOR SOLAR CELLS

A solar cell receiver (100) for use in a solar concentration system (102) that concentrates solar energy on a solar cell to convert solar energy into electricity. The solar cell receiver 100 may include a solar cell 102 mounted on a support and having one or more layers of III-V composite semiconductor. An optical element (106) may be positioned over the solar cell (102) and have an optical channel with an inlet facing away from the solar cell and an outlet facing toward the solar cell. A frame (170) may be positioned on the holder and extend around the solar cell (102) with the frame (170) having an inner side extending above the holder and facing toward the optical element (106). . An encapsulant (160) may be positioned on the support and contained between the optical element (106) and the frame (170). The encapsulant (160) may have heightened heights at points of contact with the optical element (106) and the frame (170) and a reduced height between the spaced contact points of the optical element (106) and the frame (170). The solar cell receiver (100) may be used in a solar cell module (200).

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DESCRIPTION

A SOLAR CELL RECEIVER FOR USE IN A CONCENTRATED PHOTOVOLTAIC SYSTEM USING III-V SEMICONDUCTOR SOLAR CELLS

BACKGROUND COMPARISON

Solar cells are used to convert solar or radiant energy into electricity. Historically, solar energy (both in space and terrestrially) has been predominantly provided by silicon (Si) solar cells. In the last several years, however, the high volume manufacture of high efficiency multi-junction solar cells has allowed the consideration of this alternative technology for terrestrial energy generation. In with Si, multi-function III-V cells are more radiation resistant and have higher

In general, n-in-p polarity and InGaP / (In) GaAs / Ge. Power conversion efficiencies, but tend to cost more. Some current III-V multijunction cells have energy efficiencies that exceed 27%, while silicon technologies generally achieve only about 17% efficiency. Under concentration, some current multi-function III-V cells have energy efficiencies exceeding 37%. When the need for very high power or smaller solar generators is paramount in a spacecraft or other solar power system, multijunction cells are often used instead of, or in hybrid combinations with, Si-based cells to reduce the size of the solar array. generator.

multijunction cells are composed of layers of compound III-V semiconductor multijunction cells can be grown via chemical deposition of solar composite metallurgical vapors (MOCVD) on Ge substrates. Using the Ge substrate allows a junction to be formed between n- and p-Ge. Solar cell structures can be grown on 100 mm diameter (4 inch) Ge substrates with an average mass density of approximately 86 mg / cm².

In some multijunction cells, the middle cell is an InGaAs cell as opposed to a GaAs cell. The concentration of indium may be in the range of approximately 1.5% for the InGaAs medium cell. In some implementations, such an arrangement exhibits increased efficiency. The InGaAs layers are combined substantially perfectly crosslinked with the Ge substrate.

Regardless of the type of cells used, a known problem with solar power systems is that individual solar cells can become damaged or shaded by an obstruction. For example, damage can occur as a result of exposing a solar cell to harsh environmental conditions. The current carrying capacity of a panel having one or more damaged or shaded solar cells is reduced, and the output of other panels in series with this panel tilts back the damaged or shaded cells. The voltage across the damaged or shaded cells thus increases at a reverse polarity until the full output voltage of all panels in the series is applied to the damaged or shaded cells in the panel in question. This causes damaged or shaded cells to break down.

Because a solar cell system for terrestrial applications has thousands of solar cells, its voltage output is typically in the range of hundreds of volts, and its current output is in the range of tens of amps. At these output power levels, if solar cell terminals are not protected, uncontrollable electrical discharge in the form of sparks tends to occur, and this can cause damage to the solar cells and the entire system.

The multi-function solar cell is part of a solar cell receiver that can be used in the concentrating solar cell system. Solar cell receivers can be used in environments where water, extreme heat, and humidity can erode performance and / or produce failure. Test standards and qualifications have been instituted to ensure that a solar cell receiver meets minimum requirements during use. A specific industry standard is IEC62108. Solar cell receivers should be constructed in a manner that meets the requirements of these standards to ensure proper performance.

SUMMARY

One aspect of the present specification is a module in a solar energy system in a holder, a solar cell and have one or more layers of solar cells for use in solar concentration to convert electricity that includes mounted on the III-V composite semiconductor support. , and an optical element positioned over the solar cell on an opposite side of the holder and defining an optical channel with an enlarged input facing the paired lens and a reduced output facing the solar cell concentrating solar energy on the lens. solar cell. The solar cell receiver may include a structure positioned on the support with a height above the support that is larger than the solar cell. The structure can extend around and encase the solar cell in an interior space. An encapsulant may be contained within the interior space between the optical element and the frame and may cover portions of the holder and the solar cell. The encapsulant may have an enlarged outer edge height at each of the optical element and the frame.

Of course, the present invention is not limited to the above features and advantages. Those skilled in the art will recognize additional features and advantages by reading the following detailed description, and by viewing the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will now be more fully described hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. The drawings illustrating embodiments are schematic representations not to scale. For the purpose of the present description and the appended claims, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Figure 1 is a perspective view of an implementation of a solar cell module.

Figure 2 is a perspective view of an implementation of a secondary optical element.

Figure 3 is a partially exploded perspective view of an implementation of a solar cell receiver.

Figure 4 is a partially exploded perspective view illustrating the solar cell and metallized ceramic substrate of Figure 3 in more detail.

Figure 5 is a sectional view of the solar cell, metallized ceramic substrate and heat sink along line XX 'of Figure 3.

Figure 6 is a perspective view of a solar cell receiver with a structure and encapsulant.

Figure 7 is a cross-sectional view along the line YY 'of Figure 6.

Figure 8 is a cross-sectional view of the encapsulant positioned within a frame.

Figure 9 is a cross-sectional view of the encapsulant positioned within a frame.

Figure 10 is a cross-sectional view of the encapsulant positioned within a frame.

DETAILED DESCRIPTION

Figure 1 illustrates an implementation of a solar cell module 200 comprising a lens generator 210 and corresponding solar cell receivers 100. Each of the lenses 210 is aligned with one of the solar cell receivers 100. The solar cell module 200 may be include several lens numbers 210 and solar cell receivers 100. Figure 1 includes a module 200 with fifteen lenses 210 and solar cell receivers 100 aligned on a 3x5 generator.

Lenses 210 are formed on a continuous blade 211 of optical material (e.g. acrylic). In some embodiments, regions of blade 211 not formed in lenses 210 are made partially or entirely opaque. By forming the lenses 210 off a continuous blade 211, costs can be substantially reduced. First, by producing the lens 210 on large blades, production costs are reduced. Second, assembly costs are decreased because only one item (i.e. lens blade 211) needs to be aligned with solar cell receivers 100. In this implementation, blade 211 is perched on an alignment frame 221 of an accommodation 220.

One or more vents 228 may be opening has an approximately 1

229 may extend as a filter for positioning in housing 220. The openings 228 may be positioned to facilitate air flow through the housing 220. In one embodiment, the openings 228 are positioned in the side walls of the housing 220 and approximately 3 ° C. below the lens 210. The size of the apertures 228 may vary. In one embodiment, each circular shape with a diameter of one cover through the openings 228 and act to prevent the introduction of moisture and debris into the housing 220. The cover 229 may be constructed of a variety of materials including but not limited to limited to GORETEX, nylon, and polyvinylidene.

Frame 221 may include a plurality of frame alignment elements such as holes. Alignment elements may be threaded or otherwise adapted to receive a lock. The blade 211 may include pin alignment elements, bolts or other blade hardware such as that align and engage with frame alignment elements. The frame alignment elements and the blade alignment elements are located such that by coupling the blade alignment elements with the frame alignment elements, each lens 210 is aligned with a corresponding solar cell receiver 100. Alignment elements are generally located at a central point defined by four of the lenses 210. In one embodiment, an alignment element is located at a central point defined by lenses 210a, 210b, 210c, and 210d. Another alignment element may be located at a center point defined by four other lenses 210. This model of locating the alignment elements at a center point defined by four lenses may continue along the entire blade 211.

In some embodiments, the floor surface 222 of housing 220 comprises alignment features which ensure that each solar cell receiver 100 is located at a predetermined position. These features can be coupled with each of the solar cell receptors 100.

In some implementations, each of the lenses 210 is a Fresnel lens. The corresponding solar cell receiver 100 is positioned on the surface 222 at an opposite end of the housing 220. Each of the solar cell receivers 100 includes a corresponding solar cell 102 disposed in the optical path of the corresponding lens 210, i.e. corresponding solar cell 102 receives light passing through the corresponding lens 210. In some implementations, additional optical elements are used to place the solar cell in the optical path of the lens. For example, secondary optics 104 correspond with each pair of solar cell receivers 100 and lenses 210. Secondary optics 104 gather light from lens 210 and direct it to solar cell 102 of solar cell receiver 100. In some embodiments, each solar cell receiver 100 is provided with a corresponding secondary optical element 104.

Another optical element includes a concentrator 106 which is positioned between each of the solar cell receiver pairs 100 and lenses 210. The concentrator 106 concentrates light on the solar cell 102.

While some Fresnel lenses can concentrate more sunlight than some convex lenses, implementations can use any type of 210 lens that concentrates incident sunlight. For example, either lens 210 may take the form of a biconvex lens, a planoconvex lens, or a convex-concave lens. The lenses 210 may also comprise an antireflective multilayer coating. In a module 200, each of the lenses 210 may be the same, or the module 200 may include two or more different lenses 210.

A distance X measured between the blade 211 comprising the lens 210 and the solar cells 102 of the corresponding solar cell receivers 100 may be chosen based on the focal length of the lens 210. In some embodiments, the housing 220 is arranged so that the cell Sun 102 of each respective solar cell receiver 100 is arranged at or around the focal point of the respective lens 210. In some implementations, the focal length of each lens 210 is between approximately 25.4 cm (10 inches) and 76.2 cm (30 inches). In some implementations, the focal length of each lens 210 is between approximately 38.1 cm (15 inches) and 50.8 cm (20 inches). In some implementations, the focal length of each 210 lens is 40.085 cm (17.75 inches). In some the focal length of each lens 210 varies, and the housing 220 provides multiple different distances (e.g., those that are longer and / or shorter than the distance X) between the blade 211 and the surface 222.

Housing 220 and lens blade 211 may form an enclosed interior space that protects solar cell receivers 100 from the environment.

Some implementations of lens 210 concentrate incident sunlight at 1000 times normal concentration (i.e. 1000 Suns) or more. Other implementations may include other concentrations. Overall, the efficiency of converting solar energy into electricity increases under concentrated lighting. For example, at approximately 1000 Suns, a single solar cell receiver can generate approximately implementations, watts or more of electrical power. In another example, at approximately 470 Suns or more, a single solar cell receiver can generate 14 watts or more of electrical power. The amount of electrical energy a solar cell receiver can produce may vary depending on, for example, the combination of solar cell characteristics (eg size, composition) and associated optical properties (eg concentration, focus, alignment ).

In some embodiments, the solar cells 102 of each of their respective solar cell receptors 100 is a triple junction solar cell III-V, with each of the three subcells arranged in series. In applications where multiple solar cell modules 200 are used, receivers 100 of solar cell modules 200 are typically connected together electrically in series. However, other applications may use parallel or serial-parallel connection. For example, receivers 100 within a given module 200 may be connected together electrically in series, but modules 200 are connected to each other in parallel.

As explained above, a secondary optical element (SOE) 104 may be positioned between the lens 210 and the corresponding solar cell 102. An implementation of an SOE is illustrated in FIG. 2. SOE 104 is disposed within the housing 220 of the solar cell module 200 and is generally designed to harvest solar energy concentrated by one of the corresponding lenses 210. In some embodiments, each solar cell receiver 100 has a respective SOE 104. . Other modules 200 may include less than each solar cell receiver 100 including an SOE 104.

The SOE 104 comprises an optical element 401 with an optical input 402 and an optical output 403, a body 404 and mounting tabs 405. The SOE 104 is mounted such that the optical element 401 is disposed above the cell receiver solar cell 102. corresponding solar 100. While it may vary depending on millimeters). Some 405 mounts attach to the

<td>Exit 403.</td><td>The surface</td><td colspan="2">from the inside</td>

<td>reflects</td><td>the light to</td><td>low</td><td>in</td>

<td>surface</td><td>from the inside</td><td>407 is,</td><td>in</td>

<td>coated</td><td>with silver</td><td colspan="2">or another</td>

<td>high age.</td><td>In some</td><td>cases,</td><td> 0</td>

<td>protected</td><td colspan="2">by a coating</td><td>in</td>

tapered that corresponding solar lens of the implementation, the SOE 104 is mounted such that the optical output 403 is approximately 0.5 millimeters from the solar cell 102 (e.g., the dimension

406 It is approximately 0.5 implementations, the surface flaps 222 of the housing 220. The SOE 104 may be made of metal, plastic, or glass or other materials.

In some implementations, optical element 401 has a square cross-section generally tapering from inlet 402 to

407 direction of output 403. In some embodiments, reflective material for reflective coating is passivation such as S1O2 to protect against oxidation, fogging or corrosion. The path from optical input 402 to optical output 403 forms an optical channel capturing solar energy from the

210 and guides it to the corresponding cell 102. As shown in this implementation, SOE 104 comprises an optical element 401 having four reflective walls. In other implementations, different shapes (e.g., from three sides to form a triangular cross section) may be used.

Under ideal conditions, the corresponding lens 210 associated with SOE 104 focuses light directly on solar cell 102 without light striking SOE 104. In most circumstances, lens 210 does not focus light directly on solar cell 102. This can be due to a variety of causes including, but not limited to, chromatic aberration of a refractive lens design, misalignment of solar cell 102 with lens 210 during construction, misalignment during operation due to sensor error. , structural flexion, and wind load. Thus, under most conditions, lens 210 focuses light such that it reflects off outside SOE 104. The difference between an optimal setting and a misaligned setting may be a minor variation in lens placement 210 less than 1 °. SOE 104 therefore acts as a light spill pickup to cause more light to reach solar cell 102 under circumstances when the corresponding lens 210 does not focus light directly on solar cell 102. SOE 104 may include a multi-intermediate region. reflective layers such as the type disclosed in US Patent Application Serial No. 12 / 402,814 filed March 12, 2009, which is incorporated herein by reference in its entirety.

The reflective multi-layer intermediate region may be formed from different materials and have different optical characteristics so that the reflectivity of light beams outside of SOE 104 and transmitted to solar cell 102 optimizes aggregate irradiation on the surface of solar cell 102. along the incident solar spectrum. For example, in some embodiments, inner surface 407 may be coated with silver or other material for high reflectivity. In some cases, the reflective coating is protected by a passivation coating such as SiCç to protect SOE 104 from oxidation, fogging or corrosion. SOE 104 may also homogenize (e.g. mix) the light. In some cases, it also has some concentration effect.

In some implementations, the optical input 402 is square in shape and is approximately 49.60 mm x 49.60 mm (dimension 408), the optical output is square in shape and is approximately 9.9 mm x 9.9 mm (dimension 409) and the height of the optical element is approximately 70.104 mm (dimension

410). Dimensions 408, 409, and 410 may vary with the design of solar cell module 200 and solar cell receiver 100. For example, in some implementations the dimensions of optical output 403 are approximately the same as the dimensions of solar cell 102. For an SOE 104 having these dimensions, the slope semi-angle is 15.8 degrees.

Each of the solar cells 102 may be a triple junction III-V composite semiconductor solar cell comprising an upper cell, a middle cell and a lower cell arranged in series. In another embodiment, solar cells 102 are multijunction solar cells having n-in-p polarity and are composed of InGaP / (In) GaAs III-V compounds on a Ge substrate. In each case, solar cells 102 are positioned to receive focused solar energy from SOE 104 and / or corresponding lens 210.

An anti-reflective coating may be arranged over solar cell 102. The anti-reflective coating may be a multi-layer anti-reflective coating that provides low reflectance over a certain wavelength range, for example 0.3 to 1.8 pm. An example of an anti-reflective coating is a TiO dielectric battery._x/ Al₂O3 double layer.

As shown in Figure 3, tabs 405 of SOE 104 may be configured to attach SOE 104 to a clamp 116 via one or more latches 118. Clamp 116 is provided for mounting SOE 104 to a heatsink 120 via a or more closures 122. The clamp 116 is thermally conductive so that the thermal energy generated by the SOE 104 during operation can be transferred to the heat sink 120 and dissipated.

In one embodiment as shown in Figures 3 and 4, a concentrator 106 is disposed between SOE outlet 403 output and solar cell 102. Concentrator 106 is preferably optical glass output 110. Concentrator 106 is amplified at has an inlet optics 10 &lt;

one embodiment, the concentrator 106 and directs the light

In a solid glass form, light exiting the amplified SOE 104 toward the solar cell 102. In some embodiments, the concentrator 106 has a generally square cross-section that tapers from inlet 108 to outlet 110. In some implementations, the inlet The optic 108 of the concentrator 106 has a square shape and the optical output 110 cm. The dimensions and

approximately 2 cm x 2 cm approximately 0.9 cm x 0.9 concentrator 106 may vary with the design of the solar cell module 200 and the solar cell receiver 100. For example, in some implementations the dimensions of the optical output 110 are approximately the same as the dimensions of solar cell 102. In one embodiment, concentrator 106 is a 2X concentrator. The bottom surface of the concentrator 106 may be directly bonded to the upper surface of the solar cell 102 using an adhesive 151 such as a silicone adhesive. Solar cell 102 converts light from the sun directly into electricity by the photovoltaic effect.

In some embodiments as shown in Figures 1 and 3, both an SOE 104 and a concentrator 106 are positioned along the optical path between the corresponding lens 210 and the solar cell 102. Other embodiments may include only one of these elements. optics positioned along the optical path. Other embodiments may include none of these elements along the optical path. Within a module 200, each lens pair 210 / solar cell 102 may include the same or different combinations of elements to direct the light.

As shown in Figures 3 and 4, a branch diode 124 is connected in parallel with solar cell 102.

In some implementations, diode 124 is a semiconductor device such as a Schottky branch diode or an epitaxially grown pn junction. For illustration purposes, branch diode 124 is a Schottky branch diode. External connection terminals 125 and 127 are provided for connecting solar cell 102 and diode 124 to other devices, for example, adjacent solar cell receivers (not shown).

The functionality of branch diode 124 may be appreciated by considering multiple solar cells 102 serially connected. Each solar cell 102 may be envisioned as a battery, with the cathode of each diode 124 being connected to the positive terminal of the associated battery and the anode of each diode 124 being connected to the negative terminal of the associated battery. When one of the serially connected solar cell receivers 100 becomes damaged or shaded, its voltage output is reduced or eliminated (e.g., below a threshold voltage associated with diode 124). Therefore, the associated diode 124 becomes forward biased, and a shunt current flows only through this diode 124 (and not the solar cell 102). In this way, undamaged or unshaded solar cell receivers 100 continue to generate electricity from the solar energy received by those solar cells. If not for branch diode 124, substantially all electricity produced by the other solar cell receivers would pass through the shaded or damaged solar cell receiver, destroying it, and creating an open circuit within, for example, the panel or generator. .

solar cell receiver 100 also includes a ceramic substrate 126 such as an alumina substrate for mounting solar cell 102 and heat sink 120 for dissipating heat generated by solar cell 102 during operation. Figures 4 and 5 illustrate solar cell 102 and ceramic substrate 126 in more detail. Ceramic substrate 126 has metallized upper and lower surfaces 128 and 130. Both surfaces 128 and 130 of ceramic substrate 126 are metallized to increase heat transfer capability of ceramic substrate 126, allowing the solar cell receiver 100 to better deal with the rapid temperature changes that occur due to abrupt changes in weather conditions. of solar cell operation. For example, solar cell 102 generates thermal energy when it converts light into electricity. Having both the upper and lower surfaces 128 and 130 of the ceramic substrate 126 metallized provides for faster transfer of solar cell heat energy 102 to heat sink 120 for dissipation. The opposite condition occurs when solar cell 102 suddenly becomes shaded. That is, solar cell 102 stops producing electricity and rapidly cools down as does SOE 104. The metallized upper and lower surfaces 128 and 130 of ceramic substrate 126 prevent solar cell 102 from cooling very rapidly by transferring thermal energy from heat sink 120 to solar cell 102, and depending on thermal conditions, to SOE 104 also. The increased heat transfer capability of the solar cell receiver 100 reduces the amount of stress transferred to the interface between the solar cell 102 and the ceramic substrate 126 during rapid temperature changes, ensuring a reliable solar cell-substrate interface.

Metallized upper surface 128 of ceramic substrate 126 is in contact with solar cell 102 and has separate conductive regions 132 and 134 to provide electrically isolated conductive paths to solar cell 102. First conductive region 132 provides an anode electrical contact point for solar cell 102 and second conductive region 134 provide a cathode electrical contact point for solar cell 102. Solar cell 102 has a conductive bottom surface 136 out of sight in Figure 4, but visible in the cross section of Figure 5 which is positioned over and connected to the first conductive region 132 of the metallized top surface 128 of the ceramic substrate 126. The opposite top surface 138 of solar cell 102 has a conductive contact area 140 attached to the second conductive region 134 of the ceramic substrate 126.

In one embodiment, the conductive bottom surface 136 of the solar cell 102 forms an anode terminal of the solar cell 102 and the conductive contact area 140 disposed on the upper surface 138 of the solar cell 102 forms a cathode terminal. According to this embodiment, the conductive lower surface 136 of the solar cell 102 is positioned over the first conductive region 132 of the ceramic substrate 126 and electrically isolated from the second conductive region 134 to ensure proper operation of the solar cell 102. In one embodiment, the first conductive region 132 of the ceramic substrate 126 is at least partially surrounded on all three sides by the second conductive region 134 around a peripheral region of the ceramic substrate 126.

In one embodiment, the conductive contact area 140 disposed on the upper surface 138 of the solar cell 102 occupies the perimeter of the solar cell 102. In some embodiments, the upper conductive contact area 140 may be smaller or larger to accommodate the desired type. binding. For example, the upper conductive contact area 140 may only touch one, two or three sides (or portions thereof) of the solar cell 102. In some implementations, the upper conductive contact area 140 is made as small as possible to maximize the area that converts solar energy into electricity while still allowing electrical connection. While the particular dimensions of the solar cell

102 varying depending on standard dimensions are approximately 1 cm a standard configuration approximately 12.58 mm in dimensions x 12.58 mm from the application, ² For example, it may generally be approximately 0.160 mm thick, a total active area of ​​approximately 108 mm. For example, in a solar cell 102 which is approximately 12.58 mm x 12.58 mm, the upper conductive contact area 140 may be approximately 0.98 mm wide and the active area may be approximately 10 mm x 10 mm.

The upper conductive contact area 140 of the solar cell 102 may be formed from a variety of conductive materials, for example, copper, silver, and / or gold-coated silver. In this implementation, it is the cathode (i.e. emitting) side of conductivity n of the solar cell 102 that receives the light, and accordingly, the upper conductive contact area 140 is disposed on the cathode side of the solar cell 102. In one embodiment, the upper conductive contact area 140 of the solar cell 102 is wired to the second conductive region 134 of the metallized upper surface 128 of the ceramic substrate 126 via one or more connecting wires 142. The number of connecting wires 142 used in a particular implementation may be related, among other things, to the amount of current generated by the solar cell 102. Generally, the higher the current, the greater the number of connecting wires 142 that are used.

branch diode 124 couples the first conductive region 132 of the metallized upper surface 128 of the ceramic substrate 126 to the second conductive region 134. In one embodiment, a cathode terminal of the branch diode 124 is connected to the solar cell anode terminal 102 via the first conductive region 132 of the ceramic substrate 126 and a anode terminal of branch diode 124 is electrically connected to the terminal. of solar cell cathode 102 via the second conductive region 134 of the ceramic substrate 126. The solar cell anode terminal 102 is formed by the lower conductive surface 136 of the solar cell 102 as described above and is out of sight in Figure 4, but visible in the cross section of Figure 5. The solar cell cathode terminal 102 is formed by the upper conductive contact area 140 of the solar cell 102 also as described above.

The external connection terminals 125, 127 disposed on the metallized upper surface 128 of the ceramic substrate 126 provide electrical coupling of a device to the solar cell 102 and the diode 124. In some embodiments, the connection terminals 125 and 127 correspond to terminals. anode and cathode, and are designed to accept lamp holder plugs (not shown) for connection to adjacent solar cell receivers.

The upper surface 128 of the ceramic substrate 126 may be metallized by joining metallization layers, metallization

132 and 134 to the substrate. In one form the holes 144 are formed in the layers 132, 134. Figure 4 shows the ceramic substrate 126 having two metallization layers 132 and 134 joined to the upper substrate surface 128 (the lower metallized surface is out of sight in Figure 4, but visible in the cross section of Figure 5). Corresponding protuberances may be formed on the ceramic substrate 102. The protuberances are at least partially seated in the holes 144 formed in the plating layers 132 and 134. The holes 144 in the plating layers 132 and 134 are then filled with a welder or other type of connecting material such as an adhesive, joining the layers together. 132 and 134 to the upper surface 128 of the ceramic substrate 126. The lower surface 130 of the ceramic substrate 126 may be similarly metallized. Alternatively, no protrusion is provided on the ceramic substrate 126 and the substrate is relatively flat within normal manufacturing tolerances.

Figure 5 illustrates a cross-sectional view of the solar cell 102, the ceramic substrate 126, and the solar cell receiver heat sink 120 along the line marked XX 'in Figure 3. SOE 104, the light concentrator 106 and terminals 125, 127 are not illustrated in

Figure 5 for ease of illustration. The upper and lower surfaces 128 and 130 of the ceramic substrate 126 may have protrusions that are at least partially seated in holes 144 formed in metallization layers 132, 134 and 148 to join the metallization layers to the ceramic substrate 126 as described above. Alternatively, ceramic substrate 126 is relatively normal manufacturing tolerances. On upper and lower surfaces of 126 are metallized. The upper surface 128 of substrate 126 has separate conductive regions 132 and 134 for providing electrically isolated anode and cathode connections to the solar cell 102 as described above.

Solar cell 102 has a conductive bottom surface 136 attached to the conductive region 132 of the metallized upper surface 128 of the ceramic substrate 126. In one embodiment, the conductive bottom surface 136 of the solar cell 102 forms the anode terminal of the flat solar cell within In any case, the metallised ceramic substrate

102 and the upper surface area conductive contact 140 disposed on the

138 solar cell cathode terminal of solar cell 102. conductive bottom 136 of solar cell 102 first conductive region 132

102 form the

The surface is positioned from the surface over the metallized top 128 of the electrically isolated ceramic substrate 126 of the second conductive region 134 to ensure proper operation of the solar cell 102.

The bottom surface 130 of the ceramic substrate 126 also has a metallization layer 148 which is bonded to the heat sink 120 with highly thermally conductive bonding means 150, such as a metal-filled epoxy adhesive or welder. Filling an epoxy adhesive such as silicone with metal increases the thermal conductivity of the interface between the ceramic substrate 126 and the heat sink 120, further improving the heat transfer characteristics of the solar cell receiver 100. In one embodiment, the means thermally conductive bonding joint 150 is a metal-filled epoxy adhesive having a thickness t_epoxi is about 1 to 3 mils. The metal-filled epoxy adhesive may be applied to the lower metallized surface 130 of the ceramic substrate 126, heat sink 120, or both and then cured to connect heat sink 120 to substrate 126. In one embodiment, the heat sink 120 is a one-piece extruded aluminum heat sink as shown in Figure 3.

The solar cell receiver 100 may be fabricated by providing the metallized ceramic substrate 126 and connecting the conductive lower surface 136 of the solar cell 102 to the first conductive region 132 of the metallized upper surface 128 of the substrate 126. The conductive contact area 140 disposed on the upper surface 138 of the solar cell 102 is connected to the second conductive region 134 of the metallized upper surface 128 of the ceramic substrate 126, for example via one or more connecting wires 142. The heat sink 120 is bonded to the lower metallized surface 130 of the ceramic substrate 126 with the metal-filled epoxy adhesive 150.

As shown in Figure 6, a frame 170 may be attached to the metallized upper surface 128 of the ceramic substrate 126 and extend around the solar cell 102 and related components. Frame 170 includes an open central region 174 and forms an encapsulating dam 160 that covers a portion of the solar cell receptor 100. The encapsulant 160 protects the solar cell receiver 100 from environmental elements such as water (e.g., rain, ice, snow) temperature variations, and humidity. Frame 170 may also form a shield for providing off-axis beam protection and for sealing connection terminals 125, 127.

Frame 170 may include various cross-sectional shapes when viewed in a plane extending through the lower and upper sides 172, 173. Figure 7 includes a rectangular shape with opposite inner and outer sides 171, 177, and lower and upper sides opposites 172,

173. Frame 170 may also include a variety of cross-section depending on embodiment frame 170 includes an irregular shape.

The frame 170 may be solid as in Figure 7, or may be hollow with an open interior space 178 as shown in Figure 9. Figure 9 includes the frame 170 completely surrounding the interior space 178. In another embodiment (not shown) , frame 170 basically surrounds three sides of interior space 178 with interior space 178 being exposed to the underside (i.e., opposite the upper side 173).

Frame 170 may be constructed of one or more parts. In one embodiment, frame 170 is constructed of two substantially L-shaped pieces. The exterior and interior shapes of frame 170 may vary depending on the application. The outer shape is formed by the outer sides 177 of the frame 170, and the inner shape is other application forms. In one of the

shown in inner sides 171. Figure 6 includes a frame 170 with square inner and outer shapes. The inner and outer shapes may also include, but are not limited to rectangular, circular, oval, and trapezoidal. Further, the inner and outer shapes may be the same or may be different. The frame 170 may be constructed of a variety of materials including ceramics.

Figure 7 shows a cross-sectional view of the encapsulant 160 positioned within the frame 170 and over a portion of the solar cell receiver 100. The encapsulant 160 extends over a portion of the concentrator 106, the metallized upper surface 128 of the ceramic substrate 126, portions of the solar cell 102 including the contact area 140, and the connecting wires 142 extending between the contact area 140 and the metallized upper surface 128. Encapsulant 160 is prevented from extending between concentrator 106 and solar cell 102 by a light transparent adhesive 151 that connects concentrator 106 to solar cell 102.

The encapsulant 160 is initially in a fluid form to flow into the various areas within the frame 170. The encapsulant 160 still cures to a more solid state to permanently protect the solar cell receptor 100. In one embodiment, the encapsulant 160 is SILGARD 184 available from Dow Corning Corporation.

Figure 8 is a simplified sectional view similar to Figure 7 illustrating the dimensions and placement of frame 170 and encapsulant 160. Frame 170 includes a height measured between a lower side 172 and an upper side 173. The height provides it. to the upper side 173 to be positioned along an intermediate section of the concentrator 106 and extending from the outer side of the upper metal surface 128 a greater distance than the lower side 109 of the concentrator 106. An inner side 171 of frame 170 faces toward the concentrator

106 may be plane aligned substantially perpendicular to upper metal surface 128. Inner side 171 is positioned at a distance b from the intersection of the lower and intermediate sides 109, 111 of concentrator 106. In some embodiments, distance b may be between 2 .0 mm to 5.0 mm.

The distance between frame 170 and concentrator 106 and the physical characteristics of encapsulant 160 causes high surface tension in encapsulant 160 when it is placed into interior space 178. This causes encapsulant 160 to elevate intermediate side 111 of concentrator 106 and inner side 171 of frame 170. This gives encapsulant 160 a substantially concave upper surface with enlarged inner and outer edges 161, 162 and a reduced intermediate section 163. The height of the inner and outer edges 161, 162 measured from the upper metal surface 128 is between approximately 1.0 mm and specific realization, approximately 1.75 mm.

3.0 mm. In various forms they are between heights of the heights and 1.90 mm. The encapsulants 160 may differ on the inner edge 161 than on the outer edge 162. The height of the intermediate section 163 is between 0.50 mm to 2.0 mm. In several specific embodiments, this height is between about 0.65 mm and 0.85 mm.

As shown in Figures 7 and 8, the height of the encapsulant 160 above the upper metal surface 128 is suitable to cover the connecting wires 142 (extending above surface 128 by approximately 0.35 mm and 0.40 mm). The height of the encapsulant 160 above the connecting wires 142 is between about 0.20 mm and 0.50 mm. In several specific embodiments, the height above the connecting wires 142 is between approximately 0.32 mm and 0.41 mm.

Figure 7 includes frame 170 positioned completely on top surface 128 of substrate 126. Frame 170 may also extend outwardly beyond surface 128 as shown in Figure

9 The frame 170 is positioned with the outer side 177 positioned laterally outside the surface 128 and over the heat sink 120. A material 180 is positioned between the frame 170 and the heat sink 120. The material 180 may be an adhesive for attach frame 170 to heat sink 120 and / or a seal to prevent leakage of encapsulant 160.

In one embodiment of a solar cell receiver 100 as shown in Figure 9, the bonding means 150 is SILGARD 577. SILGARD 577 is also used as an edge treatment around the lower metallized surface 130, and as the material. 180 between the frame 170 and the heat sink 120. The interior space 178 of the frame 170 is filled with a material 181. This material 181 may also be positioned around the exterior side 177 of the frame 170. In one embodiment, material 181 is silicone SS-109.

In another embodiment (not shown), frame 170 is completely positioned over heat sink 120 and does not extend over surface 128.

In one embodiment as illustrated in Figure

10, the inner side 171 of the frame 170 includes an angled section 175 disposed at an angle away from the concentrator 106. The angled section 175 extends from an intermediate point along the inner side 171 to the upper side 173 of the frame 170. In a specific embodiment, the angle of the side 175 substantially matches the angle of the intermediate side 111 of the concentrator 106. This provides for the sides 175 and 111 to be substantially parallel. The angular section

175 controls the height of the outer edge 162. Angled section 175 may also control the height of the inner edge 161. In one embodiment, the height of the inner edge 161 is the same as the height at the intersection between the inner side 171 and the section. angular 175.

Angular section 175 may extend completely around frame 170, or may be located along just one or more limited sections of frame 170. In one embodiment, a first angular section 175 extends along a first section of frame 170 and faces toward a first face of rectangular concentrator 106, and a second angular section 175 extends along a second opposite section of the frame 170 and faces a second face of the rectangular concentrator. The angle of the angular section 175 may be the same across the various sections of the frame 170, or may vary.

The frame 170 may be positioned over one or more components of the solar cell receiver 100. Figure 6 includes the frame 170 being positioned over the connector terminals 125, 127 (not shown in Figure 4). The frame 170 further includes openings 176 which receive cables 190 that connect to the connector terminals 125, 127. These openings 176 may only extend inwardly from the outer side 177 and terminate within an interior of the frame 170 away from the interior side 171 to prevent possible leakage location for the encapsulant 160. The frame 170 may further extend over the diode. branch 124. The underside 172 of frame 170 may include sections accommodating the various components. In these various embodiments, the inner side 171 of the frame 170 is positioned between the components and the solar cell 102 to provide a surface for the encapsulant 160 and to prevent encapsulant leakage.

The frame 170 may be centered around the concentrator 106 and solar cell 102. Alternatively, the frame 170 may be decentered with a section of the frame 170 being closer to the concentrator 106 and the solar cell 102 than another section.

In some embodiments, central region 174 of frame 170 is a single section. Encapsulant 160 may be introduced into central region 174 and then allowed to flow through region 174 and cover the various components. The central region 174 may also be divided into two or more separate sections. The construction of the solar cell receiver 100 requires that the encapsulant 160 be separately inserted into each of the sections.

During assembly, frame 170 is attached to substrate 126 and / or heat sink 120. An adhesive may be used for bonding and also to prevent leakage of encapsulant 160 during subsequent assembly steps.

Upon bonding of the frame 170, the encapsulant 160, which may be silicone-based, is introduced into the interior space 178. The encapsulant 160 has a surface tension that causes increased heights at the outer edges. Upon introduction, the encapsulant 160 is heat cured or other suitable process.

Solar cell 102 may be a multi-function III-V device with a number of solar subcells provided in a stacked arrangement. Solar cell 102 may include upper, middle, lower subcells having energy gaps to maximize absorption of solar energy. An applicable solar cell is disclosed in US Application Serial Application No. 12 / 148,553 filed April 18, 2008, which is incorporated herein by reference in its entirety.

Clamp 116 (Figure 3) may extend over frame 170 with latches 122 connecting heat sink 120 to points outside frame 170. A lower side of clamp 116 may be in contact with or above upper side 173 of frame 170. Alternatively, the clamp 116 may be positioned within the central region 174 of frame 170.

In various implementations described herein, a triple junction compound III-V semiconductor solar cell is used, but other types of solar cells could be used depending on the application. Solar cells 102 may be made from, for example, silicon (including amorphous, nanocrystalline, or protocrystalline), cadmium telluride, CIGS (indium copper gallium diselenide), CIS (copper and indium selenide chalcopyrite film (CuInSe2 )), gallium arsenide (eg GaAs multijunctions), light-absorbing dye (eg ruthenium metallurgical dye), or organic semiconductors (eg polyphenylene vinylene, copper phthalocyanine or carbon fullerenes).

Since a single solar cell module 200 may not produce enough electricity for a given application, two or more solar cell modules 200 may be grouped together in one generator. These generators are sometimes referred to as solar panels or panels.

While particular embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that, based on the teachings herein, changes and modifications may be made without departing from this invention and its broader aspects, and therefore , the appended claims are intended to encompass within its scope all such changes and modifications as are within the scope of this invention. Furthermore, it is to be understood that the invention is solely defined by the appended claims.

It will be understood by those of skill in the art that, in general, the terms used herein, and especially the appended claims (e.g., bodies of the appended claims) generally are intended to be open terms (for example, the term including should be interpreted as including, but not limited to, the term having shall be interpreted as having at least the term include shall be interpreted as including, but not limited to, understanding and variations thereof, such as understanding and understanding are to be construed in an open, inclusive sense, which is as including, but not limited to, etc.). It will further be understood by those of skill in the art that if a specific number of a claim recitation entered intends, such intention will be explicitly recited in the claim, and in the absence of such recitation such intention is not present. For example, as an aid to understanding, the following appended claims may contain the use of at least one and one or more introductory sentences to enter claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles one or one limits any particular claim containing such a recited claim to inventions containing only such a recitation, even when the same claim includes introductory sentences one or more or at least one and indefinite articles such as one or one (e.g. one and / or one should typically be interpreted to mean at least one or one or more); The same is true for the use of definite articles used to enter claim recitations. In addition, even if a specific number of an entered claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (for example, the mere recitation of two recitations without any other recitation). modifiers, typically means at least two recitations, or two or more recitations).

Lisbon, 20.04.2011