U.S. patent application number 13/546988 was filed with the patent office on 2013-02-07 for solar cell structure including a plurality of concentrator elements with a notch design and predetermined radii and method.
This patent application is currently assigned to Solaria Corporation. The applicant listed for this patent is Alelie Funcell, Kevin R. GIBSON. Invention is credited to Alelie Funcell, Kevin R. GIBSON.
Application Number | 20130032194 13/546988 |
Document ID | / |
Family ID | 45351353 |
Filed Date | 2013-02-07 |
United States Patent
Application |
20130032194 |
Kind Code |
A1 |
GIBSON; Kevin R. ; et
al. |
February 7, 2013 |
SOLAR CELL STRUCTURE INCLUDING A PLURALITY OF CONCENTRATOR ELEMENTS
WITH A NOTCH DESIGN AND PREDETERMINED RADII AND METHOD
Abstract
A solar cell concentrator structure includes a first
concentrator element having a first aperture region and a first
exit region including a first back surface region and a first
corner region. The structure also includes a second concentrator
element integrally formed with the first concentrator element. The
second concentrator element includes a second aperture region and a
second exit region-including a second back surface region and a
second corner region. Additionally, the structure includes a first
radius of curvature of 0.10 mm and less characterizing the first
corner structure and the second corner structure, a first coupling
region between the first exit region and a first surface region of
a first photovoltaic device. The structure further includes a
second radius of curvature of 0.10 mm and less characterizing a
region between the first concentrator element and the second
concentrator element.
Inventors: |
GIBSON; Kevin R.; (Redwood
City, CA) ; Funcell; Alelie; (Fremont, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GIBSON; Kevin R.
Funcell; Alelie |
Redwood City
Fremont |
CA
CA |
US
US |
|
|
Assignee: |
Solaria Corporation
Fremont
CA
|
Family ID: |
45351353 |
Appl. No.: |
13/546988 |
Filed: |
July 11, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13171389 |
Jun 28, 2011 |
8242351 |
|
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13546988 |
|
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|
12423806 |
Apr 15, 2009 |
|
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13171389 |
|
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Current U.S.
Class: |
136/246 ;
136/259 |
Current CPC
Class: |
H01L 31/0543 20141201;
Y02E 10/52 20130101; G02B 5/045 20130101; H01L 31/0547 20141201;
H01L 31/048 20130101; F24S 23/00 20180501 |
Class at
Publication: |
136/246 ;
136/259 |
International
Class: |
H01L 31/052 20060101
H01L031/052; H01L 31/0232 20060101 H01L031/0232 |
Claims
1. A solar module comprising: a solar cell concentrator structure
comprising: a thickness of glass material ranging from 5 mm to 7
mm, the thickness of glass material comprising a plurality of
integrally formed concentrator elements including a first
concentrator element configured in a first shape having a first
curved wall region, the first concentrator element including a
first aperture region and a first exit region, the first exit
region including a first back surface region; and a second
concentrator element configured in a second shape having a second
curved wall region and the second concentrator element being
integrally formed with the first concentrator element, the second
concentrator element including a second aperture region and a
second exit region, the second exit region including a second back
surface region; a separation region provided between the first
concentrator element and the second concentrator element, the
separation region being characterized by a width separating the
first exit region from the second exit region; a second radius of
curvature characterizing a region between the first concentrator
element and the second concentrator element, the second radius of
curvature being less than about 0.10 mm and greater than 0.001 mm;
a geometric concentration range from about 1.8 to 4.5
characterizing the first concentrator element and the second
concentrator element; a triangular shaped region including an apex
defined by the second radius of curvature and a base defined by the
separation region; and a refractive index of about 1 characterizing
the triangular region; a plurality of photovoltaic devices
comprising a first photovoltaic device comprising a first surface
region coupled to the first exit region and a second photovoltaic
device comprising a second surface region coupled to the second
exit region.
2. The solar module of claim 1 wherein the second exit region
includes a second corner region and the first exit region includes
a first corner region and further comprising a first radius of
curvature characterizing the first corner structure, the first
radius of curvature being less than 0.10 mm and greater than 0.001
mm.
3. The solar module of claim 1 wherein the first concentrator
element integrally formed with the second concentrator element are
essentially a single piece of the glass material.
4. The solar module of claim 1 wherein the first concentrator
element integrally formed with the second concentrator element is
molded.
5. The solar module of claim 1 wherein the first concentrator
element and the second concentrator element are characterized by a
refractive index of about 1.4 and greater.
6. The solar module of claim 1 wherein the first concentrator is
characterized by a first truncated pyramid shape and the second
concentrator is characterized by a second truncated pyramid
shape.
7. The solar module of claim 1 wherein the coupling region
comprises an optical coupling material.
8. The solar module of claim 1 wherein the optical coupling
material comprises an optical grade epoxy, or ethylene vinyl
acetate (EVA), or silicones, or polyurethanes.
9. The solar module of claim 1 wherein the first concentrator
element is optically coupled to a first photovoltaic region and the
second concentrator element is optically coupled to a second
photovoltaic region.
10. The solar module of claim 1 wherein the second radius of
curvature is greater than an amount that causes a crack within a
portion of a thickness of the glass material.
11. A solar module apparatus comprising a cell concentrator
structure, the solar cell concentrator structure comprising: a
piece of optical material made of glass characterized by a first
spatial direction and a second spatial direction, the first spatial
direction being normal to the second spatial direction; a first
concentrator element and a second concentrator element provided
within a first portion of the piece of optical material and a
second portion of the piece of optical material, respectively,
defined along the second spatial direction, the first concentrator
element and the second concentrator element having a thickness of 5
mm to 7 mm; an aperture region provided on a first surface region
of the piece of optical material, the aperture region being adapted
to allow electromagnetic radiation to be illuminated thereon; an
exit region provided on a second surface region of the piece of
optical material; a separation region provided between the first
concentrator element and the second concentrator element, the
separation region being characterized by a width; a second radius
of curvature of 0.10 mm and less within a predetermined depth of
the piece of optical material, the second radius of curvature being
provided between the first concentrator element and the second
concentrator element.
12. The solar module apparatus of claim 11 wherein the piece of
optical material is essentially the glass material; wherein the
first concentrator element characterized by a first radius of
curvature.
13. The solar module apparatus of claim 11 wherein the second
radius of curvature reduces an efficiency of the first concentrator
element and the second concentrator element by about 50% and
less.
14. The solar module apparatus of claim 11 wherein the piece of
optical material is characterized by a refractive index of about
1.4 and more.
15. The solar module apparatus of claim 11 wherein the second
radius of curvature is an apex of a triangular region having a base
provided within a portion of a first exit region of the first
concentrator element and a second exit region of the second
concentrator element.
16. The solar module apparatus of claim 11 wherein the second
radius of curvature is an apex of a triangular region having a base
provided within a portion of a first exit region of the first
concentrator element and a second exit region of the second
concentrator element, the triangular region having a refractive
index of about 1.0.
17. A solar module comprising a solar cell concentrator structure,
the solar cell concentrator structure comprising: a plurality of
concentrator elements integrally formed with each other, the
plurality of concentrator elements including a first concentrator
element, the first concentrator element including a first aperture
region and a first exit region, the first exit region including a
first back surface region, the first concentrator element being
characterized by a refractive index of about 1.4 and greater, and a
second concentrator element integrally formed with the first
concentrator element, the second concentrator element being
characterized by a refractive index of about 1.4 and greater, the
second concentrator element including a second aperture region and
a second exit region, the second exit region including a second
back surface region, the first concentrator element integrally
formed with the second concentrator element being essentially a
single piece of molded glass material, the first concentrator
element being optically coupled to a first photovoltaic region and
the second concentrator element being optically coupled to a second
photovoltaic region; a thickness of 5 mm to 7 mm characterizing the
first concentrator element and the second concentrator element; a
first coupling region between the first exit region and a first
surface region of a first photovoltaic device, the first coupling
region including an optical coupling material comprising an EVA
material; a second coupling region between the second exit region
and a second surface region of a second photovoltaic device; a
separation region provided between the first concentrator element
and the second concentrator element, the separation region being
characterized by a width separating the first exit region from the
second exit region; a radius of curvature characterizing a region
between the first concentrator element and the second concentrator
element, the radius of curvature being about between 0.001 mm and
0.10 mm; a triangular shaped region including an apex defined by
the radius of curvature and a base defined by the separation
region; a refractive index of about 1 characterizing the triangular
region; and a plurality of photovoltaic devices including the first
photovoltaic device and the second photovoltaic device.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
patent application Ser. No. 13/171,389 filed on Jun. 28, 2011,
which is a continuation-in-part application claiming priority to
U.S. patent application Ser. No. 12/423,806, filed Apr. 15, 2009,
which claims priority to U.S. application Ser. No. 12/060,769,
filed Apr. 1, 2008, which claims priority to U.S. Provisional
Application No. 61/019,135, filed Jan. 4, 2008, and U.S.
Provisional Application No. 60/969,949, filed Sep. 5, 2007. U.S.
patent application Ser. No. 12/423,806 also claims priority to U.S.
patent application Ser. No. 12/360,078, filed Jan. 26, 2009. U.S.
patent application Ser. No. 12/423,806 further claims priority to
U.S. patent application Ser. No. 11/695,566, filed Apr. 2, 2007.
U.S. patent application Ser. No. 12/423,806 is related to U.S.
patent application Ser. No. 11/445,933, filed Jun. 2, 2006 and Ser.
No. 12/200,921, filed Apr. 14, 2009. All of these applications are
commonly assigned and incorporated by reference herein for all
purposes.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to solar energy
techniques. In particular, the present invention provides a method
and resulting device fabricated from a plurality of concentrating
elements respectively coupled to a plurality of photovoltaic
regions. More particularly, the present method and structure are
directed to a notch structure provided between a pair of
concentrating elements. In a specific embodiment, the notch
structure is implemented to improve efficiency of the multiple
concentrator structure. Merely by way of example, the invention has
been applied to solar panels, commonly termed modules, but it would
be recognized that the invention has a much broader range of
applicability.
[0003] As the population of the world increases, industrial
expansion has led to an equally large consumption of energy. Energy
often comes from fossil fuels, including coal and oil,
hydroelectric plants, nuclear sources, and others. As merely an
example, the International Energy Agency projects further increases
in oil consumption, with developing nations such as China and India
accounting for most of the increase. Almost every element of our
daily lives depends, in part, on oil, which is becoming
increasingly scarce. As time further progresses, an era of "cheap"
and plentiful oil is coming to an end. Accordingly, other and
alternative sources of energy have been developed.
[0004] Concurrent with oil, we have also relied upon other very
useful sources of energy such as hydroelectric, nuclear, and the
like to provide our electricity needs. As an example, most of our
conventional electricity requirements for home and business use
come from turbines run on coal or other forms of fossil fuel,
nuclear power generation plants, and hydroelectric plants, as well
as other forms of renewable energy. Often times, home and business
use of electrical power has been stable and widespread.
[0005] Most importantly, much if not all of the useful energy found
on the Earth comes from our sun. Generally all common plant life on
the Earth achieves life using photosynthesis processes from sun
light. Fossil fuels such as oil were also developed from biological
materials derived from energy associated with the sun. For human
beings including "sun worshipers," sunlight has been essential. For
life on the planet Earth, the sun has been our most important
energy source and fuel for modem day solar energy.
[0006] Solar energy possesses many characteristics that are very
desirable! Solar energy is renewable, clean, abundant, and often
widespread. Certain technologies developed often capture solar
energy, concentrate it, store it, and convert it into other useful
forms of energy.
[0007] Solar panels have been developed to convert sunlight into
energy. As merely an example, solar thermal panels often convert
electromagnetic radiation from the sun into thermal energy for
heating homes, running certain industrial processes, or driving
high grade turbines to generate electricity. As another example,
solar photovoltaic panels convert sunlight directly into
electricity for a variety of applications. Solar panels are
generally composed of an array of solar cells, which are
interconnected to each other. The cells are often arranged in
series and/or parallel groups of cells in series. Accordingly,
solar panels have great potential to benefit our nation, security,
and human users. They can even diversify our energy requirements
and reduce the world's dependence on oil and other potentially
detrimental sources of energy.
[0008] Although solar panels have been used successfully for
certain applications, there are still certain limitations. Solar
cells are often costly. Depending upon the geographic region, there
are often financial subsidies from governmental entities for
purchasing solar panels, which often cannot compete with the direct
purchase of electricity from public power companies. Additionally,
the panels are often composed of silicon bearing wafer materials.
Such wafer materials are often costly and difficult to manufacture
efficiently on a large scale. Availability of solar panels is also
somewhat scarce. That is, solar panels are often difficult to find
and purchase from limited sources of photovoltaic silicon bearing
materials. These and other limitations are described throughout the
present specification, and may be described in more detail
below.
[0009] From the above, it is seen that techniques for improving
solar devices is highly desirable.
BRIEF SUMMARY OF THE INVENTION
[0010] The present invention relates generally to solar energy
techniques. In particular, the present invention provides a method
and resulting device fabricated from a plurality of concentrating
elements respectively coupled to a plurality of photovoltaic
regions. More particularly, the present method and structure are
directed to a notch structure provided between a pair of
concentrating elements. In a specific embodiment, the notch
structure is implemented to improve efficiency of the multiple
concentrator structure. Merely by way of example, the invention has
been applied to solar panels, commonly termed modules, but it would
be recognized that the invention has a much broader range of
applicability.
[0011] In a specific embodiment, the present invention provides a
solar cell concentrator structure. The solar cell concentrator
structure includes a first concentrator element. The first
concentrator element includes a first aperture region and a first
exit region. The first exit region includes a first back surface
region and a first corner region. The solar cell concentrator
structure further includes a second concentrator element integrally
formed with the first concentrator element. The second concentrator
element includes a second aperture region and a second exit region.
The second exit region includes a second back surface region and a
second corner region. Additionally, the solar cell concentrator
structure includes a first radius of curvature of about 0.25 mm and
less characterizing the first corner structure and the second
corner structure. In certain embodiments, the first radius of
curvature is 0.10 mm to 0.001 mm, or 0.10 mm to 0.005 mm, 0.15 mm
to 0.005 mm, or 0.15 mm to 0.001 mm, or 0.25 mm to 0.001 mm, or
0.25 mm to 0.005 mm. The solar cell concentrator structure also
includes a first coupling region between the first exit region and
a first surface region of a first photovoltaic device and a second
coupling region between the second exit region and a second surface
region of a second photovoltaic device. Moreover, the solar cell
concentrator structure includes a separation region provided
between the first concentrator element and the second concentrator
element. The separation region is characterized by a width
separating the first exit region from the second exit region.
Furthermore, the solar cell concentrator structure includes a
second radius of curvature of about 0.15 mm and less characterizing
a region between the first concentrator element and the second
concentrator element, a triangular shaped region including an apex
defined by the radius of curvature and a base defined by the
separation region, and a refractive index of about 1 characterizing
the triangular region.
[0012] In another specific embodiment, the invention provides a
solar module concentrator structure. The solar module concentrator
structure includes a plurality of elongated concentrating units.
Each of the plurality of elongated concentrating units comprises a
concentrator element. The concentrator element includes an aperture
region and an exit region. The exit region includes a back surface
region and a corner structure. Each of the plurality of elongated
concentrating units also includes a radius of curvature of about
0.25 mm and less characterizing the corner structure and a coupling
region between the exit region and a photovoltaic region.
[0013] In yet another specific embodiment, the present invention
provides a solar cell concentrator structure. The solar cell
concentrator structure includes a piece of optical material
characterized by a first spatial direction and a second spatial
direction. The first spatial direction is normal to the second
spatial direction. The solar cell concentrator structure further
includes a first concentrator element and a second concentrator
element provided within a first portion of the piece of optical
material and a second portion of the piece of optical material,
respectively, defined along the second spatial direction.
Additionally, the solar cell concentrator structure includes an
aperture region provided on a first surface region of the piece of
optical material. The aperture region is adapted to allow
electromagnetic radiation to be illuminated thereon. The solar cell
concentrator structure also includes an exit region provided on a
second surface region of the piece of optical material. The exit
region is adapted to allow electromagnetic radiation to be
outputted and is characterized by a corner region having a first
radius of curvature of about 0.25 mm and less. Moreover, the solar
cell concentrator structure includes a separation region provided
between the first concentrator element and the second concentrator
element. The separation region is characterized by a width within a
vicinity of the exit region. Furthermore, the solar cell
concentrator structure includes a radius of curvature of about 0.15
mm and less within a predetermined depth of the piece of optical
material. The radius of curvature is provided between the first
concentrator element and the second concentrator element.
[0014] In an alternative embodiment, the present invention provides
a method for manufacturing a solar cell. The method includes a step
of providing a solar concentrator structure. The structure includes
a first concentrator element with a first aperture region and a
first exit region and a second concentrator element integrally
formed with the first concentrator element. The second concentrator
element includes a second aperture region and a second exit region.
The solar concentrator structure also includes a separation region
provided between the first concentrator element and the second
concentrator element. The separation region is characterized by a
width separating the first exit region from the second exit region.
Additionally, the solar concentrator structure includes a radius of
curvature of about 0.15 mm and less characterizing a region between
the first concentrator element and the second concentrator element
and a triangular region including an apex formed by the radius of
curvature and a base formed by the separation region. Moreover, the
solar concentrator structure includes a refractive index of about
1.0 characterizing the triangular region. The method further
includes a step of coupling a first photovoltaic region to the
first concentrator element and a step of coupling a second
photovoltaic region to the second concentrator element.
[0015] In another alternative embodiment, the invention provides a
solar concentrator structure. The solar concentrator structure
includes a thickness of material characterized along a first
spatial direction including at least a first concentrator element
and a second concentrator element provided within a first portion
of the thickness of material and a second portion of the thickness
of material defined along a second spatial direction, the first
concentrator element and the second concentrator element having a
thickness of 5 mm to 7 mm. The solar concentrator structure also
includes an aperture region provided on a first surface region of
the thickness of material. The aperture region is adapted to allow
electromagnetic radiation to be illuminated thereon. Additionally,
the solar concentrator structure includes an exit region provided
on a second surface region of the thickness of material. The exit
region is adapted to allow electromagnetic radiation to be
outputted. Moreover, the solar concentrator structure includes a
separation region provided between the first concentrator element
and the second concentrator element. The separation region is
characterized by a width within a vicinity of the exit region.
Furthermore, the solar concentrator structure includes a radius of
curvature of about 0.15 mm and less within a predetermined depth of
the thickness of material.
[0016] Many benefits are achieved by way of the present invention
over conventional techniques. For example, the invention provides
for an improved solar cell concentrator structure for manufacture
of solar module. Such solar concentrator structure uses a single
piece of polymeric or glass webbing or a combination integrally
including a plurality of elongated concentrating units each
comprising a geometric light concentrator element coupled to one of
a plurality of photovoltaic strips. In a preferred embodiment, the
geometric light concentrator element has a geometric concentration
characteristic with an aperture to exit ratio in a range from about
1.8 to about 4.5 and the exit region includes two exit notches with
a radius of curvature of about 0.25 mm and less characterizing the
corresponding two corner structures. In another preferred
embodiment, between the exit region of the concentrator element and
a photovoltaic strip there is a coupling region that is configured
to have its refractive index matched and accommodate the radius of
the exit notches. The use of concentrator according to the present
invention helps the solar conversion module having less
photovoltaic material per surface area (e.g., 80% or less, 50% or
less) than conventional solar panel module. Depending upon the
embodiment, one or more of these benefits may be achieved. These
and other benefits will be described in more detail throughout the
present specification and more particularly below.
[0017] Various additional objects, features and advantages of the
present invention can be more fully appreciated with reference to
the detailed description and accompanying drawings that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a simplified diagram of a solar cell according to
an embodiment of the present invention;
[0019] FIG. 2 is a simplified diagram of solar cell concentrating
elements according to an embodiment of the present invention;
[0020] FIG. 2A is a simplified side-view diagram of solar cell
concentrating elements according to an embodiment of the present
invention;
[0021] FIG. 3 is a simplified diagram of a plurality of notch
structures for a solar cell concentrator according to an embodiment
of the present invention;
[0022] FIG. 4 is a more detailed diagram of a notch structure for a
solar cell concentrator according to an embodiment of the present
invention;
[0023] FIG. 5 is a plot of irradiation loss as a function of notch
structure size according to an embodiment of the present
invention;
[0024] FIG. 6 is a simplified diagram of a coupling region provided
between an exit region of an concentrator element and a
photovoltaic region according to an embodiment of the present
invention;
[0025] FIG. 7 is a plot of concentration ratio as a function of
corner structure size of a solar cell concentrator according to an
embodiment of the present invention; and
[0026] FIG. 8 is a plot of irradiation loss as a function of corner
structure of the solar concentrator according to an embodiment of
the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0027] According to the present invention, techniques related to
solar energy are provided. In particular, the present invention
provides a method and resulting device fabricated from a plurality
of concentrating elements respectively coupled to a plurality of
photovoltaic regions. More particularly, the present method and
structure are directed to a notch structure provided between a pair
of concentrating elements. In a specific embodiment, the notch
structure is implemented to improve efficiency of the multiple
concentrator structure. Merely by way of example, the invention has
been applied to solar panels, commonly termed modules, but it would
be recognized that the invention has a much broader range of
applicability.
[0028] FIG. 1 is a simplified diagram of a solar cell according to
an embodiment of the present invention. This diagram is merely an
example, which should not unduly limit the scope of the claims
herein. One of ordinary skill in the art would recognize other
variations, modifications, and alternatives. As shown is an
expanded view of the present solar cell device structure, which
includes various elements. The device has a back cover member 101,
which includes a surface area and a back area. The back cover
member also has a plurality of sites, which are spatially disposed,
for electrical members, such as bus bars, and a plurality of
photovoltaic regions. Alternatively, the back cover can be free
from any patterns and is merely provided for support and packaging.
Of course, there can be other variations, modifications, and
alternatives.
[0029] In a preferred embodiment, the device has a plurality of
photovoltaic strips 105, each of which is disposed overlying the
surface area of the back cover member. In a preferred embodiment,
the plurality of photovoltaic strips corresponds to a cumulative
area occupying a total photovoltaic spatial region, which is active
and converts sunlight into electrical energy.
[0030] An encapsulating material 115 is overlying a portion of the
back cover member. That is, an encapsulating material forms
overlying the plurality of strips, and exposed regions of the back
cover, and electrical members. In a preferred embodiment, the
encapsulating material can be a single layer, multiple layers, or
portions of layers, depending upon the application. In alternative
embodiments, as noted, the encapsulating material can be provided
overlying a portion of the photovoltaic strips or a surface region
of the front cover member, which would be coupled to the plurality
of photovoltaic strips. Of course, there can be other variations,
modifications, and alternatives.
[0031] In a specific embodiment, a front cover member 121 is
coupled to the encapsulating material. That is, the front cover
member is formed overlying the encapsulate to form a multilayered
structure including at least the back cover, bus bars, plurality of
photovoltaic strips, encapsulate, and front cover. In a preferred
embodiment, the front cover includes one or more concentrating
elements, which concentrate (e.g., intensify per unit area)
sunlight onto the plurality of photovoltaic strips. That is, each
of the concentrating elements can be associated respectively with
each of or at least one of the photovoltaic strips.
[0032] Upon assembly of the back cover, bus bars, photovoltaic
strips, encapsulate, and front cover, an interface region is
provided along at least a peripheral region of the back cover
member and the front cover member. The interface region may also be
provided surrounding each of the strips or certain groups of the
strips depending upon the embodiment. The device has a sealed
region and is formed on at least the interface region to form an
individual solar cell from the back cover member and the front
cover member. The sealed region maintains the active regions,
including photovoltaic strips, in a controlled environment free
from external effects, such as weather, mechanical handling,
environmental conditions, and other influences that may degrade the
quality of the solar cell. Additionally, the sealed region and/or
sealed member (e.g., two substrates) protect certain optical
characteristics associated with the solar cell and also protects
and maintains any of the electrical conductive members, such as bus
bars, interconnects, and the like. Of course, there can be other
benefits achieved using the sealed member structure according to
other embodiments.
[0033] In a preferred embodiment, the total photovoltaic spatial
region occupies a smaller spatial region than the surface area of
the back cover. That is, the total photovoltaic spatial region uses
less silicon than conventional solar cells for a given solar cell
size. In a preferred embodiment, the total photovoltaic spatial
region occupies about 80% and less of the surface area of the back
cover for the individual solar cell. Depending upon the embodiment,
the photovoltaic spatial region may also occupy about 70% and less
or 60% and less or preferably 50% and less of the surface area of
the back cover or given area of a solar cell. Of course, there can
be other percentages that have not been expressly recited according
to other embodiments. Here, the terms "back cover member" and
"front cover member" are provided for illustrative purposes, and
not intended to limit the scope of the claims to a particular
configuration relative to a spatial orientation according to a
specific embodiment. Further details of each of the various
elements in the solar cell can be found throughout the present
specification and more particularly below.
[0034] In a specific embodiment, the present invention provides a
packaged solar cell assembly being capable of stand-alone operation
to generate power using the packaged solar cell assembly and/or
with other solar cell assemblies. The packaged solar cell assembly
includes rigid front cover member having a front cover surface area
and a plurality of concentrating elements thereon. Depending upon
applications, the rigid front cover member consists of a variety of
materials. For example, the rigid front cover is made of polymer
material. As another example, the rigid front cover is made of
transparent polymer material having a reflective index of about 1.4
or 1.42 or greater. According to an example, the rigid front cover
has a Young's Modulus of a suitable range. Each of the
concentrating elements has a length extending from a first portion
of the front cover surface area to a second portion of the front
cover surface area. Each of the concentrating elements has a width
provided between the first portion and the second portion. Each of
the concentrating elements having a first edge region coupled to a
first side of the width and a second edge region provided on a
second side of the width. The first edge region and the second edge
region extend from the first portion of the front cover surface
area to a second portion of the front cover surface area. The
plurality of concentrating elements is configured in a parallel
manner extending from the first portion to the second portion.
[0035] It is to be appreciated that embodiment can have many
variations. For example, the embodiment may further includes a
first electrode member that is coupled to a first region of each of
the plurality of photovoltaic strips and a second electrode member
coupled to a second region of each of the plurality of photovoltaic
strips.
[0036] As another example, the solar cell assembly additionally
includes a first electrode member coupled to a first region of each
of the plurality of photovoltaic strips and a second electrode
member coupled to a second region of each of the plurality of
photovoltaic strips. The first electrode includes a first
protruding portion extending from a first portion of the sandwiched
assembly and the second electrode comprising a second protruding
portion extending from a second portion of the sandwiched
assembly.
[0037] In yet another specific embodiment, the present invention
provides a solar cell apparatus. The solar cell apparatus includes
a backside substrate member comprising a backside surface region
and an inner surface region. Depending upon application, the
backside substrate member can be made from various materials. For
example, the backside member is characterized by a polymer
material.
[0038] In yet another embodiment, the present invention provides a
solar cell apparatus that includes a backside substrate member. The
backside substrate member includes a backside surface region and an
inner surface region. The backside substrate member is
characterized by a width. For example, the backside substrate
member is characterized by a length of about eight inches and less.
As an example, the backside substrate member is characterized by a
width of about 8 inches and less and a length of more than 8
inches. Of course, there can be other variations, modifications,
and alternatives. Further details of the solar cell assembly can be
found in U.S. patent application Ser. No. 11/445,933 (Attorney
Docket No.: 906RO-000210US), commonly assigned, and hereby
incorporated by reference herein.
[0039] FIG. 2 is a simplified diagram of solar cell concentrating
elements according to an embodiment of the present invention. This
diagram is merely an example, which should not unduly limit the
scope of the claims herein. One of ordinary skill in the art would
recognize other variations, modifications, and alternatives. As
shown, each of the concentrating elements for the strip
configuration includes a trapezoidal shaped member. Each of the
trapezoidal shaped members has a bottom surface 201 coupled to a
pyramidal shaped region 205 coupled to an upper region 207. The
upper region is defined by surface 209, which is co-extensive of
the front cover. Each of the members is spatially disposed and in
parallel to each other according to a specific embodiment. Here,
the term "trapezoidal" or "pyramidal" may include embodiments with
straight or curved or a combination of straight and curved walls
according to embodiments of the present invention. Depending upon
the embodiment, the concentrating elements may be on the front
cover, integrated into the front cover, and/or be coupled to the
front cover according to embodiments of the present invention.
Further details of the front cover with concentrating elements are
provided more particularly below.
[0040] In a specific embodiment, a solar cell apparatus includes a
shaped concentrator device operably coupled to each of the
plurality of photovoltaic strips. The shaped concentrator device
has a first side and a second side. In addition, the solar cell
apparatus includes an aperture region provided on the first side of
the shaped concentrator device. As merely an example, the
concentrator device includes a first side region and a second side
region. Depending upon application, the first side region is
characterized by a roughness of about 100 nanometers or 120
nanometers RMS and less, and the second side region is
characterized by a roughness of about 100 nanometers or 120
nanometers RMS and less. For example, the roughness is
characterized by a dimension value of about 10% of a light
wavelength derived from the aperture regions. Depending upon
applications, the backside member can have a pyramid-type
shape.
[0041] As an example, the solar cell apparatus includes an exit
region provided on the second side of the shaped concentrator
device. In addition, the solar cell apparatus includes a geometric
concentration characteristic provided by a ratio of the aperture
region to the exit region. The ratio can be characterized by a
range from about 1.8 to about 4.5. The solar cell apparatus also
includes a polymer material characterizing the shaped concentrator
device. The solar cell apparatus additionally includes a refractive
index of about 1.45 and greater characterizing the polymer material
of the shaped concentrator device. Additionally, the solar cell
apparatus includes a coupling material formed overlying each of the
plurality of photovoltaic strips and coupling each of the plurality
of photovoltaic regions to each of the concentrator devices. For
example, the coupling material is characterized by a suitable
Young's Modulus.
[0042] As merely an example, the solar cell apparatus includes a
refractive index of about 1.45 and greater characterizing the
coupling material coupling each of the plurality of photovoltaic
regions to each of the concentrator device. Depending upon
application, the polymer material is characterized by a thermal
expansion constant that is suitable to withstand changes due to
thermal expansion of elements of the solar cell apparatus.
[0043] For certain applications, the plurality of concentrating
elements has a light entrance area (A1) and a light exit area (A2)
such that A2/A1 is 0.8 and less. As merely an example, the
plurality of concentrating elements has a light entrance area (A1)
and a light exit area (A2) such that A2/A1 is 0.8 and less, and the
plurality of photo voltaic strips are coupled against the light
exit area. In a preferred embodiment, the ratio of A2/A1 is about
0.5 and less. For example, each of the concentrating elements has a
height of 7 mm or less. In a specific embodiment, the sealed
sandwiched assembly has a width ranging from about 100 millimeters
to about 210 millimeters and a length ranging from about 100
millimeters to about 210 millimeters. In a specific embodiment, the
sealed sandwiched assembly can even have a length of about 300
millimeters and greater. As another example, each of the
concentrating elements has a pair of sides. In a specific
embodiment, each of the sides has a surface finish of 100
nanometers or less or 120 nanometers and less RMS. Of course, there
can be other variations, modifications, and alternatives.
[0044] Referring now to FIG. 2A, the front cover has been
illustrated using a side view 201, which is similar to FIG. 2. The
front cover also has a top-view illustration 210. A section view
220 from "B-B" has also been illustrated. A detailed view "A" of at
least two of the concentrating elements 230 is also shown.
Depending upon the embodiment, there can be other variations,
modifications, and alternatives.
[0045] Depending upon the embodiment, the concentrating elements
are made of a suitable material. The concentrating elements can be
made of a polymer, glass, or other optically transparent materials,
including any combination of these, and the like. The suitable
material is preferably environmentally stable and can withstand
environmental temperatures, weather, and other "outdoor"
conditions. The concentrating elements can also include portions
that are coated with an anti-reflective coating for improved
efficiency. Coatings can also be used for improving a durability of
the concentrating elements. Of course, there can be other
variations, modifications, and alternatives.
[0046] In a specific embodiment, the solar cell apparatus includes
a first reflective side provided between a first portion of the
aperture region and a first portion of the exit region. As merely
an example, the first reflective side includes a first polished
surface of a portion of the polymer material. For certain
applications, the first reflective side is characterized by a
surface roughness of about 120 nanometers RMS and less.
[0047] Moreover, the solar cell apparatus includes a second
reflective side provided between a second portion of the aperture
region and a second portion of the exit region. For example, the
second reflective side comprises a second polished surface of a
portion of the polymer material. For certain applications, the
second reflective side is characterized by a surface roughness of
about 120 nanometers and less. As an example, the first reflective
side and the second reflective side provide for total internal
reflection of one or more photons provided from the aperture
region.
[0048] In addition, the solar cell apparatus includes a geometric
concentration characteristic provided by a ratio of the aperture
region to the exit region. The ratio is characterized by a range
from about 1.8 to about 4.5. Additionally, the solar cell apparatus
includes a polymer material characterizing the shaped concentrator
device, which includes the aperture region, exit region, first
reflective side, and second reflective side. As an example, the
polymer material is capable of being free from damaged caused by
ultraviolet radiation.
[0049] Furthermore, the solar cell apparatus has a refractive index
of about 1.45 and greater characterizing the polymeric and/or glass
material of the shaped concentrator device. Moreover, the solar
cell apparatus includes a coupling material formed overlying each
of the plurality of photovoltaic strips and coupling each of the
plurality of photovoltaic regions to each of the concentrator
devices. The solar cell apparatus additionally includes one or more
pocket regions facing each of the first reflective side and the
second reflective side. The one or more pocket regions can be
characterized by a refractive index of about 1 to cause one or more
photons from the aperture region to be reflected toward the exit
region. To maintain good efficiency of the subject concentrator
devices, each of the concentrating elements is separated by a
region having a notch structure of a predetermined size and shape
according to a specific embodiment. Additionally, the exit region
of each of the shaped concentrator device includes a corner
structure having a first predetermined size and shape to also allow
for good efficiency of the subject concentrator devices. Further
details of the notch structures and the corner structures can be
found throughout the present specification and more particularly
below.
[0050] FIG. 3 is a simplified diagram of a plurality of notch
structures and corner structures for a solar cell concentrator 300
according to an embodiment of the present invention. This diagram
is merely an example, which should not unduly limit the scope of
the claims herein. One of ordinary skill in the art would recognize
other variations, modifications, and alternatives. As shown, the
concentrator structure has a first concentrator element 301, which
includes a first aperture region 304 and a first exit region 306.
The concentrator structure also includes a second concentrator
element 302 integrally formed with the first concentrator element.
In a specific embodiment, the second concentrator element includes
a second aperture region 308 and a second exit region 310.
[0051] In a specific embodiment, the concentrator structure has a
separation region 312 provided between the first concentrator
element and the second concentrator element. The separation region
is characterized by a width 314 separating the first exit region
from the second exit region. As shown the separation region
includes a triangular shaped region--having an apex 316 defined by
a radius of curvature of 0.15 mm and less and a base defined by the
separation region. In a specific embodiment, the triangular region
has a refractive index of about one, which can be essentially an
air gap and/or other non-solid open region. The apex of the
triangular region is provided within a thickness of material 318 of
the concentrator structure. Also shown in FIG. 3, each of the
concentrator elements includes a first corner structure 320 and a
second corner structure 322 in a portion of the exit region. The
corner structure 322 is characterized by an exit radius curvature.
The exit radius curvature is predetermined in conjunction with the
radius of curvature of the apex 316 to optimize performance of the
solar cell. In addition, the manufacturing costs, structural
integrity, and/or strength may also be a consideration in
determining the exit radius. For example, the exit radius is
greater than a critical radius where the concentrator structure is
likely to crack. More detailed discuss is provide below.
[0052] FIG. 4 is a more detailed diagram of a notch structure for a
solar cell concentrator according to an embodiment of the present
invention. This diagram is merely an example, which should not
unduly limit the scope of the claims herein. One of ordinary skill
in the art would recognize other variations, modifications, and
alternatives. As shown in FIG. 4, the apex of the triangular region
includes a notch structure characterized by an apex region 401 and
wall regions 403. In a specific embodiment, the wall regions are
straight. In certain other embodiments, the wall region may be
curved. The notch structure describes a portion of a cross section
of a triangular channel region provided between a first solar
concentration element and a second solar concentration element. The
term "notch" is not intended to be limited to the specification but
should be construed by a common interpretation of the term. In a
specific embodiment, the apex region is characterized by a radius
of curvature 405. In a specific embodiment, the radius of curvature
can be greater than about 0.001 mm. In an alternative embodiment,
the radius of curvature can range from 0.05 mm to about 0.15 mm.
Preferably, a minimum of radius of curvature is provided to
maintain a structure/mechanical integrity of the solar cell
concentrator in the temperature range of about -40 deg Celsius and
85 deg Celsius in accordance with IEC (International
Electrotechnical Commission) 61215 specification according to a
specific embodiment. Of course there can be other modifications,
variations, and alternatives.
[0053] FIG. 5 is a more detailed diagram illustrating a corner
structure 506 of a concentrator element 502 according to an
embodiment of the present invention. As shown, an exit region 504
is optically coupled to a photovoltaic region 508 in a specific
embodiment. In a specific embodiment, the corner structure 506 is
characterized by an exit radius of curvature 510. In a specific
embodiment, the exit radius of curvature can be greater than about
0.001 mm. In an alternative embodiment, the exit radius of
curvature can range from 0.025 to 0.15 mm. As explained above, the
exit radius of the curvature is optimized to maintain an efficient
transmission of electromagnetic radiation to the photovoltaic
region in a specific embodiment. For example, the curvature 510 is
determined using a variety of factors, such as the refractive index
(and/or other optical properties) of the concentrator element, the
angle of the exit aperture 316 illustrated in FIG. 3, and/or other
factors. Of course there can be other variations, modifications,
and alternatives.
[0054] In one embodiment, the solar concentrator can be made of
materials selected from acrylic, or diamond, or quartz, or glass,
or a combination of those materials. In a specific embodiment, the
solar concentrator is fabricated using a mold having an edge radius
of curvature of less than 0.15 mm. The material for making the
concentrator can be injected through a fan gate, or a valve gate,
or an extrusion filling the mold. The structural components may
include a compression component and a heating component. The
heating component may generate heat during the molding process via
current or through an external heating source. Of course there can
be other variations, modifications, and alternatives.
[0055] Also shown in FIG. 6, a coupling region 602 can be provided
between an exit region of a concentrator element and a photovoltaic
region. Like references are used in the present Figure and others
and not intended to be limited. Merely for the purpose of
illustration, various structures are not drawn in scale. In a
specific embodiment, the exit region is optically coupled to the
photovoltaic region using an optical coupling material within the
coupling region. Examples of such optical coupling material can
include optical grade epoxy, ethylene vinyl acetate (EVA),
silicones, polyurethanes, and others. In a specific embodiment, the
optical coupling material includes polyurethanes provided in a
thickness of 0.025 to 0.25 mm. Of course one skilled in the art
would recognize other variations, modifications, and
alternatives.
[0056] FIG. 7 is a plot of concentration ratio as a function of
corner structure size of a solar cell concentrator according to an
embodiment of the present invention. This diagram is merely an
example, which should not unduly limit the scope of the claims
herein. One of ordinary skill in the art would recognize other
variations, modifications, and alternatives. As shown, the vertical
axis illustrates concentration ratio and the horizontal axis
illustrates notch structure size or radius of curvature. The result
was obtained using a solar cell concentrator with an entrance of 4
mm and an exit of 2 mm. The concentration ratio generally decreases
with an increase in exit radius of curvature of the corner
structure. A corresponding plot of irradiation loss as a function
of corner structure is shown in FIG. 8. As shown, the vertical axis
illustrates percent of light loss or irradiation loss and the
horizontal axis illustrates exit radius of curvature of the corner
structure. The irradiation loss generally increases with an
increase of exit radius. In a specific embodiment, the exit radius
of curvature is optimized to allow for a maximum concentration
ratio or a minimum scattering loss and to allow for maintaining
mechanical/structural integrity of the solar cell concentrator in
the temperature range between about -40 deg Celsius and 85 deg
Celsius according to IEC 61215 specifications according to a
preferred embodiment.
[0057] It is also understood that the examples and embodiments
described herein are for illustrative purposes only and that
various modifications or changes in light thereof will be suggested
to persons skilled in the art and are to be included within the
spirit and purview of this application and scope of the appended
claims.
* * * * *