U.S. patent application number 13/666263 was filed with the patent office on 2013-05-02 for thermoelectric device technology.
This patent application is currently assigned to Cardinal Solar Technologies Company. The applicant listed for this patent is Cardinal Solar Technologies Company. Invention is credited to Klaus Hartig.
Application Number | 20130104952 13/666263 |
Document ID | / |
Family ID | 47221569 |
Filed Date | 2013-05-02 |
United States Patent
Application |
20130104952 |
Kind Code |
A1 |
Hartig; Klaus |
May 2, 2013 |
Thermoelectric Device Technology
Abstract
A thermoelectric device for use with solar cells or other heat
sources. A substrate has a manufactured surface with a plurality of
highland features and lowland features. Each highland feature
defines a peak adjacent to which there is an interface of two
different film regions (formed of two different metals, two
different semiconductors, or one metal and one semiconductor). The
two film regions diverge away from each other with increasing
distance from the interface and terminate at distal end regions. In
response to a temperature difference between the interface and the
distal end regions, the device produces a voltage.
Inventors: |
Hartig; Klaus; (Avoca,
WI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cardinal Solar Technologies Company; |
Eden Prairie |
|
MN |
|
|
Assignee: |
Cardinal Solar Technologies
Company
Eden Prairie
MN
|
Family ID: |
47221569 |
Appl. No.: |
13/666263 |
Filed: |
November 1, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61554654 |
Nov 2, 2011 |
|
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|
Current U.S.
Class: |
136/206 ;
257/E31.131; 438/54 |
Current CPC
Class: |
H02S 10/10 20141201;
C23C 14/34 20130101; Y02E 10/50 20130101; H01L 35/32 20130101; H01L
35/34 20130101 |
Class at
Publication: |
136/206 ; 438/54;
257/E31.131 |
International
Class: |
H01L 35/02 20060101
H01L035/02; H01L 31/04 20060101 H01L031/04; H01L 35/34 20060101
H01L035/34 |
Claims
1. A thermoelectric device comprising a substrate having a
manufactured surface comprising a plurality of highland features
and a plurality of lowland features, each highland feature defining
a peak adjacent to which there is an interface of two different
film regions.
2. The thermoelectric device of claim 1 wherein the two different
film regions are either formed of two different metals, two
different semiconductors, or one metal and one semiconductor.
3. The thermoelectric device of claim 1 wherein, at the interface,
the two different film regions come together in an end-to-end
fashion.
4. The thermoelectric device of claim 1 wherein the two different
film regions diverge away from each other with increasing distance
from the interface and terminate at distal end regions.
5. The thermoelectric device of claim 4 wherein the lowland
features comprise valleys, and the distal end regions of the two
different film regions are located in two adjacent valleys.
6. The thermoelectric device of claim 4 wherein in response to a
temperature difference between the interface and the distal end
regions of the two different film regions, the device produces a
voltage.
7. The thermoelectric device of claim 6 wherein the voltage is
proportional to said temperature difference.
8. The thermoelectric device of claim 1 wherein the manufactured
surface is covered, at least in part, by a coating comprising a
number of first film regions and a number of second film regions,
the first film regions comprising a first film composition, the
second film regions comprising a second film composition, the first
and second film compositions being different, the coating being
arranged such that each first film region extends between a peak
interface with one second film region and a valley interface with
another second film region, and each second film region extends
between a peak interface with one first film region and a valley
interface with another first film region.
9. The thermoelectric device of claim 1 wherein the two different
film regions each comprise a thin film having a thickness of
between 0.1 micron and 20 microns.
10. The thermoelectric device of claim 9 wherein the thickness is
between 0.5 micron and 10 microns.
11. The thermoelectric device of claim 10 wherein the thickness is
between 0.5 micron and 5 microns.
12. The thermoelectric device of claim 1 wherein the plurality of
highland features and the plurality of lowland features
respectively comprise a plurality of peaks and a plurality of
valleys, wherein a set of first surfaces facing a first common
direction are coated with a first film composition, and a set of
second surfaces facing a second common direction are coated with a
second film composition.
13. The thermoelectric device of claim 12 wherein the substrate is
a sheet-like substrate.
14. The thermoelectric device of claim 12 wherein the substrate is
a glass sheet, and the manufactured surface is a patterned glass
surface.
15. The thermoelectric device of claim 1 wherein the substrate is
provided in combination with a heat source device, the manufactured
surface of the substrate being carried against the heat source
device such that the highland features contact the heat source
device.
16. The thermoelectric device of claim 15 wherein the heat source
device is a photovoltaic device having opposed front and rear
faces, the front face of the device being adapted to receive
incident solar radiation, the manufactured surface of the substrate
being carried against the photovoltaic device such that the
highland features contact the rear face of the photovoltaic
device.
17. The thermoelectric device of claim 16 wherein thermal
insulation spaces are defined between the lowland features of the
thermoelectric device and the rear face of the photovoltaic
device.
18. The thermoelectric device of claim 1 wherein the peak is
characterized by a generally triangular, mountain-like
configuration in cross section.
19. The thermoelectric device of claim 14 wherein the glass sheet
has a major dimension of at least 30 inches.
20. A thermoelectric device comprising a glass sheet having a
patterned surface comprising a plurality of peaks and a plurality
of valleys, wherein coated onto each peak are two different film
regions, wherein at an apex of each peak there is an interface of
the two different film regions, and wherein the two different film
regions diverge away from each other with increasing distance from
the interface and terminate at distal end regions, the two
different film regions together forming a thermocouple such that in
response to a temperature difference between the interface and the
distal end regions of the two different film regions, the device
produces a voltage.
21. The thermoelectric device of claim 20 wherein the glass sheet
has a major dimension of at least 30 inches.
22. The thermoelectric device of claim 21 wherein the glass sheet
has a major dimension of at least 40 inches.
23. The thermoelectric device of claim 20 wherein the glass sheet
is soda-lime glass.
24. The thermoelectric device of claim 20 wherein the two different
film regions each comprise a thin film having a thickness of
between 0.5 micron and 10 microns, and the two different film
regions are either formed of two different metals, two different
semiconductors, or one metal and one semiconductor.
25. A photovoltaic, thermoelectric module comprising a photovoltaic
device and a thermoelectric device, the photovoltaic device having
opposed front and rear faces and including a front electrode, a
rear electrode, and a photovoltaic film between the front and rear
electrodes, the front face of the photovoltaic device being adapted
to receive incident solar radiation, the thermoelectric device
comprising a substrate having a manufactured surface comprising a
plurality of highland features and a plurality of lowland features,
each highland feature defining a peak adjacent to which there is an
interface of two different film regions, the manufactured surface
of the substrate being carried against the photovoltaic device such
that the highland features contact the rear face of the
photovoltaic device.
26. The module of claim 25 wherein, at the interface, the two
different film regions come together in an end-to-end fashion, the
interface being located at a contact location where the peak
contacts the rear face of the photovoltaic device.
27. The module of claim 25 wherein the two different film regions
diverge away from each other with increasing distance from the
interface and terminate at distal end regions, and wherein in
response to a temperature difference between the interface and the
distal end regions of the two different film regions, the device
produces a voltage, the voltage being proportional to said
temperature difference.
28. The module of claim 27 wherein the lowland features comprise
valleys, and the distal end regions of the two different film
regions are located in two adjacent valleys.
29. The module of claim 25 wherein thermal insulation spaces are
defined between the lowland features of the substrate and the rear
face of the photovoltaic device.
30. The module of claim 25 wherein the plurality of highland
features and the plurality of lowland features respectively
comprise a plurality of peaks and a plurality of valleys, wherein a
set of first surfaces facing a first common direction are coated
with a first film composition, and a set of second surfaces facing
a second common direction are coated with a second film
composition.
31. The module of claim 25 wherein the two different film regions
are either formed of two different metals, two different
semiconductors, or one metal and one semiconductor.
32. The module of claim 25 wherein the substrate is a glass sheet,
and the manufactured surface is a patterned glass surface.
33. A method of producing a thermoelectric device, the method
comprising: a) providing a substrate having a manufactured surface
comprising a plurality of peaks and a plurality of valleys, wherein
a set of first surfaces face a first common direction, and a set of
second surfaces face a second common direction, the first surfaces
being on one side of the peaks, the second surfaces being on
another side of the peaks, b) performing a first directional
coating operation so as to deposit a first film composition on the
first surfaces, and performing a second directional coating
operation so as to deposit a second film composition on the second
surfaces, such that after performing said first and second coating
operations, adjacent each peak there is an interface of two
different film regions, one comprising the first film composition,
the other comprising the second film composition, the two different
film regions diverging away from each other with increasing
distance from the interface and terminating at distal end regions,
wherein in response to a temperature difference between the
interface and the distal end regions of the two different film
regions, the device produces a voltage.
34. The method of claim 33 wherein the first and second directional
coating operations comprise vacuum deposition techniques.
35. The method of claim 33 wherein the first and second directional
coating operations comprise sputter deposition techniques.
36. The method of claim 33 wherein the first film composition and
the second film composition are each deposited to a thickness of
between 0.1 microns and 20 microns.
37. The method of claim 33 wherein the first film composition and
the second film composition are either formed of two different
metals, two different semiconductors, or one metal and one
semiconductor.
38. The method of claim 33 wherein the substrate is a glass sheet
having a major dimension of at least 30 inches.
39. The method of claim 33 wherein the second directional coating
operation is performed after the first directional coating
operation has been completed.
40. The method of claim 33 further including providing a
photovoltaic device having opposed front and rear faces and
comprising a front electrode, a rear electrode, and a photovoltaic
film between the front and rear electrodes, the front face of the
photovoltaic device being adapted to receive incident solar
radiation, the method comprising coupling the substrate to the
photovoltaic device such that the peaks of the substrate's
manufactured surface contact the rear face of the photovoltaic
device.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to devices that generate
electricity using the thermoelectric effect. In particular, this
invention relates to a thermoelectric device that can be used with
solar cells or other devices that are characterized by having a
high temperature.
BACKGROUND OF THE INVENTION
[0002] The thermoelectric effect is well known. It involves
converting a temperature difference into an electric voltage, or
vice versa. When a thermoelectric device has two sides at different
temperatures (i.e., a hot side and a cold side), the device creates
a voltage.
[0003] Many machines, devices, and other objects generate a great
deal of heat that is never recycled in any way, but rather is lost
as waste heat. As just one example, solar cells use some of the
radiation that strikes them, but waste a great deal of energy in
the form of heat. It has therefore previously been suggested that
increased efficiency may be obtained by providing a combined solar
cell/thermoelectric device. See U.S. Pat. No. 4,710,588 (Hughes
Aircraft Company), which focuses on a combined solar
cell/thermoelectric device for aerospace applications.
[0004] It would be desirable to provide improved thermoelectric
devices that provide a practical option for use with solar cells
and other devices, machines, or objects that generate, emit, and/or
possess heat.
SUMMARY OF THE INVENTION
[0005] In certain embodiments, the invention provides a
thermoelectric device comprising a substrate having a manufactured
surface comprising a plurality of highland features and a plurality
of lowland features. Preferably, each highland feature defines a
peak adjacent to which there is an interface of two different film
regions.
[0006] Some embodiments of the invention provide a thermoelectric
device comprising a glass sheet having a patterned surface that
includes a plurality of peaks and a plurality of valleys. Coated
onto each peak are two different film regions. At an apex of each
peak, there is an interface of the two different film regions, and
the two different film regions diverge away from each other with
increasing distance from the interface and terminate at distal end
regions. The two different film regions together form a
thermocouple such that in response to a temperature difference
between the interface and the distal end regions of the two
different film regions, the device produces a voltage.
[0007] Certain embodiments of the invention provide a photovoltaic,
thermoelectric module comprising a photovoltaic device and a
thermoelectric device. The photovoltaic device has opposed front
and rear faces and includes a front electrode, a rear electrode,
and a photovoltaic film between the front and rear electrodes. The
front face of the photovoltaic device is adapted to receive
incident solar radiation. The thermoelectric device comprises a
substrate having a manufactured surface comprising a plurality of
highland features and a plurality of lowland features. Each
highland feature defines a peak adjacent to which there is an
interface of two different film regions. In the present
embodiments, the manufactured surface of the substrate is carried
against the photovoltaic device such that the highland features
contact the rear face of the photovoltaic device.
[0008] In some embodiments, the invention provides a method of
producing a thermoelectric device. The method involves providing a
substrate having a manufactured surface comprising a plurality of
peaks and a plurality of valleys. A set of first surfaces face a
first common direction, and a set of second surfaces face a second
common direction. The first surfaces are on one side of the peaks,
while the second surfaces are on another side of the peaks. A first
directional coating operation is performed so as to deposit a first
film composition on the first surfaces, and a second directional
coating operation so as to deposit a second film composition on the
second surfaces. After performing the first and second coating
operations, adjacent each peak there is an interface of two
different film regions, one comprising the first film composition,
the other comprising the second film composition. The two different
film regions diverge away from each other with increasing distance
from the interface and terminate at distal end regions. In response
to a temperature difference between the interface and the distal
end regions of the two different film regions, the device produces
a voltage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a broken away schematic cross sectional view of a
substrate having a manufactured surface comprising a plurality of
peaks and a plurality of valleys in accordance with certain
embodiments of the present invention.
[0010] FIG. 2 is a broken away schematic cross sectional view of
the substrate of FIG. 1, depicting a first directional coating
angle in accordance with certain embodiments of the invention.
[0011] FIG. 3 is a broken away schematic cross sectional view of
the substrate of FIG. 1, shown after being coated from the first
directional coating angle of FIG. 2.
[0012] FIG. 4 is a broken away schematic cross sectional view of
the substrate of FIG. 3, depicting a second directional coating
angle in accordance with certain embodiments of the invention.
[0013] FIG. 5 is a broken away schematic cross sectional view of
the coated substrate of FIG. 3, shown after being coated from the
second directional coating angle of FIG. 4, the resulting coated
substrate forming a thermoelectric device in accordance with
certain embodiments of the invention.
[0014] FIG. 6 is a broken away schematic cross sectional view of an
exemplary thermoelectric device coupled to a heat source device in
accordance with certain embodiments of the invention.
[0015] FIG. 7 is a broken away cross sectional detail view of
region AA from FIG. 6.
[0016] FIG. 8 is a broken away schematic cross sectional view of an
exemplary thermoelectric device coupled to a photovoltaic device in
accordance with certain embodiments of the invention.
[0017] FIG. 9 is a broken away cross sectional detail view of
region BB from FIG. 8.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0018] The following detailed description is to be read with
reference to the drawings, in which like elements in different
drawings have like reference numerals. The drawings, which are not
necessarily to scale, depict selected embodiments and are not
intended to limit the scope of the invention. Skilled artisans will
recognize that the examples provided herein have many useful
alternatives that fall within the scope of the invention.
[0019] Many machines, devices, and other objects generate, emit,
and/or possess (at least at certain times) a great deal of heat
that is never recycled, but rather is lost as waste heat. Solar
cells, for example, use some of the radiation that strikes them,
but waste a lot of energy in the form of heat. As another example,
spandrels on buildings can become quite hot, e.g., by virtue of the
solar radiation incident upon them. While there may be exceptions,
the heat from spandrels typically is not recycled in any way. The
situation is similar with many furnaces, air conditioners, and
other HVAC components that generate or emit heat. Similarly, the
heat from many engines is lost as waste heat. These (and all other
such machines, devices, and objects) are broadly referred to herein
as "heat source devices."
[0020] The present invention provides a thermoelectric device
adapted for use with a heat source device. In certain embodiments,
the heat source device presents (e.g., has) a hot surface, a hot
body, or some other hot area (at least some of the time, e.g.,
during operation or use) to which the thermoelectric device can be
(e.g., is) coupled. In other embodiments, the heat source device
presents a cold surface, a cold body, or some other cold area to
which the thermoelectric device can be (e.g., is) coupled.
[0021] FIG. 6 is a schematic illustration of a heat source device
HD to which there is coupled a thermoelectric device 100 in
accordance with certain embodiments of the invention. Here, the
illustrated heat source device HD has a hot surface (or hot face)
HS to which the thermoelectric device is coupled. The illustrated
hot surface HS preferably comprises (e.g., is) planar or
substantially planar. While this is by no means required, such a
configuration lends itself nicely to certain preferred designs of
the present thermoelectric device 100, as discussed below.
[0022] Preferably, the thermoelectric device 100 is carried
against, or otherwise connected thermally to, the hot surface HS of
the heat source device HD. For example, the thermoelectric device
100 can optionally be carried against the heat source device HD
such that multiple lines of thermal contact, points of thermal
contact, and/or other localized regions of thermal contact are
provided between the heat source device HD and the thermoelectric
device 100. In some preferred embodiments, a pattern of thermal
contact (e.g., a predetermined thermal contact pattern) is provided
between the heat source device HD and the thermoelectric device
100. More will be said of this later.
[0023] The thermoelectric device 100 comprises a substrate 10
having a manufactured surface (or a manufactured face, side, or
another type of manufactured interface) 15, which can optionally
have a plurality of highland features P and a plurality of lowland
features V. Reference is made to FIG. 2. Here, each illustrated
highland feature P comprises a peak, and each lowland feature V
comprises a valley, although this is not required. The illustrated
peak configuration terminates at a tip-like apex. However, other
peak configurations are contemplated. For example, the peaks may
have rounded or flat apex regions. Similarly, while the lowland
features V are shown as valleys that terminate in sharp V-shaped
bottoms, the bottoms of other suitable lowland features may be
rounded, flat, etc.
[0024] The illustrated peaks and valleys of the manufactured
surface 15 can optionally be elongated so as to extend (or "run")
parallel to one another across a length or width of the substrate
(or they may run crosswise at an angle across the substrate). In
such cases, each valley can optionally be located (e.g., defined)
between two adjacent peaks. In other embodiments, rather than
providing a manufactured surface having a field of elongated
channels and peaks, it is possible to provide peaks shaped like
individual cones, pyramids, spikes, etc.
[0025] The substrate 10 can be chosen from a wide variety of
transparent or opaque substrate types. In many cases, the substrate
10 will comprise glass, e.g., it can optionally be a glass sheet.
If desired, the glass can be soda-lime glass. In other embodiments,
the substrate can be plastic. In some cases, it is plexiglass. It
may also be a plate of metal, e.g., copper, in which case it would
preferably have an electrically insulating cover (e.g., film) over
its manufactured surface.
[0026] In some embodiments, the substrate (which can optionally be
glass sheet or another sheet-like substrate) has a major dimension
of at least 30 inches, at least 40 inches, or at least 42 inches.
The major dimension can, for example, be a length or width of the
substrate. The dimensions (e.g., ranges) mentioned in this
disclosure are merely exemplary; they are not limiting to the
invention.
[0027] Thus, substrates of various sizes can be used in the present
invention. Commonly, large-area substrates are used. Certain
embodiments involve a substrate 10 having a major dimension (e.g.,
a length or width) of at least 0.5 meter, such as at least 1 meter,
at least 1.5 meters (e.g., between 2 and 4 meters), or perhaps even
greater than 3 meters. In some cases, the substrate will be
rectangular, although this is by no means required.
[0028] In some embodiments, the substrate 10 is a generally square
or rectangular glass sheet. The substrate in these embodiments can
optionally have any of the dimensions described in the preceding
paragraph, in the following paragraph, or both.
[0029] Substrates of various thicknesses can be used in the present
invention. In some embodiments, the substrate 10 (which can
optionally be a glass sheet) has a thickness of about 1-5 mm.
Certain embodiments involve a substrate 10 with a thickness of
between about 2.3 mm and about 4.8 mm, such as between about 2.5 mm
and about 4.8 mm. In one particular embodiment, a sheet of glass
(e.g., soda-lime glass) with a thickness of about 3 mm is used. In
one group of embodiments, the thickness of the substrate is between
about 4 mm and about 20 mm. When the substrate is float glass, it
will commonly have a thickness of between about 4 mm and about 19
mm. In another group of embodiments, the substrate is a thin sheet
having a thickness of between about 0.35 mm and about 1.9 mm. It is
to be appreciated that different substrate thicknesses can be
chosen to meet the requirements of different embodiments.
[0030] In preferred embodiments, the substrate 10 is a sheet of
patterned glass. In such cases, the surface 15 of the glass can be
patterned using any glass patterning process suitable for producing
the desired pattern. In the illustrated embodiments, the glass
surface is patterned with a series of peaks and valleys. Many other
patterns can be used, however, to provide the desired highland and
lowland features. Examples include a field of pyramids, cones,
spiral-shaped ridges, or combinations thereof. Thus, the
illustrated pattern is by no limiting to the invention.
[0031] Suitable patterned glass can obtained commercially from a
variety of sources, including Cardinal FG Company of Menomonie,
Wis., USA. Alternatively, patterned glass can be made using well
known glass patterning methods, such as those taught in U.S. Pat.
Nos. 5,224,978 and 6,708,526, as well as in U.S. Patent Application
Publication No. 2010/0154862, the contents of each of which are
hereby incorporated herein by reference.
[0032] FIG. 1 depicts an exemplary substrate 10 having a
manufactured surface 15 with a plurality of highland P and lowland
V features. As noted above, the substrate 10 can optionally be
patterned glass. In the embodiment of FIG. 2, the substrate's
manufactured surface 15 comprises a plurality of peaks P and a
plurality of valleys V, and a set of first surfaces A face a first
common direction, while a set of second surfaces B face a second
common direction. Here, the first surfaces A are on one side of the
peaks P, while the second surfaces B are on another side (e.g., an
opposite side) of the peaks.
[0033] As can be appreciated by referring to FIGS. 2-5, the
invention provides methods wherein a first directional coating
operation is performed so as to deposit a first film composition on
the first surfaces A, and a second directional coating operation is
performed so as to deposit a second film composition on the second
surfaces B. Preferably, the second directional coating operation is
performed after the first directional coating operation has been
completed. After the coating operations have been completed,
adjacent each peak P (e.g., at an apex or a top region thereof)
there preferably is an interface IF of two different film regions
AF, BF, one AF comprising the first film composition, the other BF
comprising the second film composition. This is perhaps best seen
in FIG. 7.
[0034] Various directional coating techniques can be used. In some
cases, the first and second directional coating operations are
directional vacuum deposition techniques. Directional sputtering,
for example, is one suitable technique. Other directional coating
techniques can be used, such as directional evaporation, electron
beam evaporation, spray coating, galvanizing, electroplating,
etc.
[0035] Thus, the coating technique used to produce the noted first
AF and second BF film regions preferably involves a flux of coating
material that travels substantially in a single direction (the
arrows AD and BD, shown respectively in FIGS. 2 and 4, each
represent such a directional flux of coating material). The
directional coating technique can thus be used to create a
shadowing phenomenon. For example, with the illustrated
peaks-and-valleys surface 15, during the first directional coating
operation (see FIGS. 2 and 3), the shadowing involves the noted
first surfaces A being coated selectively, e.g., such that
immediately following the first directional coating operation, the
second surfaces B are coating free, substantially coating free, or
at least have uncoated regions.
[0036] The foregoing sentence assumes that no coating has been
applied to the manufactured surface 15 prior to the first coating
operation; but that need not be the case. For example, it may be
desirable to deposit one or more films onto the manufactured
surface 15 before performing the noted first directional coating
operation. Examples include adhesion-promoter films, electrical
insulator films, sodium ion diffusion barrier films, etc. It may
therefore simply be the case that, immediately following the first
directional coating operation, the second surfaces B are free of
the first film composition, substantially free of the first film
composition, or at least have regions that are not coated with the
first film composition.
[0037] Similarly, with a peaks-and-valleys surface 15 like that
illustrated, during the second directional coating operation (see
FIGS. 4 and 5), the shadowing involves the noted second surfaces B
being coated selectively, e.g., such that immediately following the
second directional coating operation, the first surfaces A are free
of the second film composition, substantially free of the second
film composition, or at least have regions that are not coated with
the second film composition.
[0038] Thus, the first surfaces A of the manufactured surface 15
can be coated from one angle (see FIG. 2), and the second surfaces
B can be coated from another angle. These two angles preferably are
separated from each other by greater than 45 degrees, and more
preferably greater than 60 degrees, such as by about 65-115
degrees, perhaps optimally by about 90 degrees. In some
embodiments, the flux of the first coating composition travels in a
direction AD that is substantially perpendicular to the noted first
surfaces A, while the flux of the second coating composition
travels in a direction BD that is substantially perpendicular to
the noted second surfaces B.
[0039] In FIGS. 2 and 3, the illustrated peaks P shadow the second
surfaces B during the first coating operation. Similarly, when the
second surfaces B are coated from the other angle, i.e., during the
second coating operation (see FIG. 4), the peaks P shadow the first
surfaces A. The resulting coated substrate (see FIG. 5) has,
adjacent to each peak P (e.g., at an apex thereof), an interface IF
of two different film regions AF, BF, one film region AF comprising
(or consisting essentially of, or consisting of) the first film
composition, the other film region BF comprising (or consisting
essentially of, or consisting of) the second film composition.
[0040] In the embodiments shown in FIGS. 5-7, two different film
regions AF, BF diverge away from each other with increasing
distance from the interface IF and terminate at distal end regions
DER (see FIG. 7). The film materials and thicknesses of the two
film regions AF, BF are selected such that, in response to a
temperature difference between the interface IF and the distal end
regions DER of the two different film regions, the device 100
produces a voltage. Preferably, the voltage is proportional to a
temperature difference between the interface IF and the distal end
regions DER. Thus, the two different film regions AF, BF (e.g.,
each coupled pair of film regions AF, BF) preferably together form
a thermocouple.
[0041] To produce such a thermocouple, the first film composition
(i.e., first film region AF) and the second film composition (i.e.,
second film region BF) preferably are either formed of two
different metals (the term "metal" here includes metal alloys), two
different semiconductors, or one metal and one semiconductor. Thus,
in the present device, two different conductors (optionally two
different metal alloys) preferably produce a voltage proportional
to a temperature difference between hot and cold ends of the
device.
[0042] Insofar as the thickness of the coating is concerned, the
first film composition and the second film composition are each
preferably deposited to a thickness of between 0.1 microns and 20
microns, such as between about 0.5 microns and 10 microns, or
between about 0.5 microns and 5 microns.
[0043] As noted above, on the resulting coated substrate, each
highland feature P preferably defines a peak adjacent to which
there is an interface IF of two different film regions AF, BF. The
interface IF can optionally be at an apex of the peak, as
illustrated.
[0044] In embodiments like those exemplified by FIGS. 5-7, at the
interface IF, the two different film regions AF, BF come together
in an end-to-end fashion. While there may well be some overlap of
the two films adjacent the interface, the two film regions AF, BF
preferably are characterized by being provided in an end-to-end
arrangement, rather than being one film coated over the entirety of
the other film.
[0045] Thus, the two different film regions AF, BF preferably
diverge away from each other with increasing distance from the
interface IF and terminate at distal end regions DER. In such
embodiments, in response to a temperature difference between the
interface IF and the distal end regions DER of the two different
film regions AF, BF, the device 100 produces a voltage, which
preferably is proportional to the temperature difference. It may
therefore be desirable to maximize this temperature difference. In
a solar cell, for example, the back side of the solar cell may be
exposed to an ambient environment and may therefore be cooled
naturally by wind, convection, etc. Furthermore, the back of such a
solar cell could be provided with a flow of cooling fluid or
another cooling means, if desired.
[0046] In the illustrated configuration of the coated surface 15,
the lowland features V comprise valleys, and the distal end regions
DER of the two different film regions AF, BF are located in two
adjacent valleys. In such embodiments, the valleys preferably are
not occupied by any solid material, but rather are simply occupied
by gas.
[0047] The present thermoelectric device 100 preferably comprises a
number of thermocouples. Thus, at least part of the manufactured
surface 15 preferably is covered by a coating comprising a number
of first film regions AF and a number of second film regions BF. As
noted above, the first film regions AF comprise a first film
composition, and the second film regions BF comprise a second film
composition. The first AF and second BF film compositions are
different (this can include a base film material be doped with one
dopant for the first film region while being doped with a different
dopant for the second film region). In the illustrated design, the
coating is arranged such that each first film region AF extends
between a peak interface with one second film region and a valley
interface with another second film region, while each second film
region extends between a peak interface with one first film region
and a valley interface with another first film region. This is best
shown in FIGS. 5 and 6.
[0048] Thus, certain embodiments of the thermoelectric device 100
are characterized by having a plurality of highland features and a
plurality of lowland features that respectively comprise a
plurality of peaks and a plurality of valleys, and where a set of
first surfaces A facing a first common direction are coated with a
first film composition, and a set of second surfaces B facing a
second common direction are coated with a second film
composition.
[0049] The invention also provides embodiments wherein the
thermoelectric device 100 is provided in combination with a heat
source device HD. Reference is made to FIGS. 6-9. Here, the
manufactured surface 15 of the substrate 10 is carried against the
heat source device HD such that the highland features P contact the
heat source device. As noted above, the heat source device HD can
be a machine, device, or another object that generates, emits,
and/or possesses heat. In some embodiments, the heat source device
HD is a photovoltaic device (e.g., a solar cell) SC having opposed
front ST and rear HS faces. In such embodiments, the photovoltaic
device SC can optionally take the form of a panel.
[0050] Referring to FIG. 9, the front face ST of the photovoltaic
device SC preferably is adapted to receive incident solar
radiation, and the manufactured surface 15 of the thermoelectric
device 100 preferably is carried against the photovoltaic device
such that the highland features P contact the rear surface HS of
the photovoltaic device 100.
[0051] In embodiments of this nature, by providing small areas of
contact between the thermoelectric device 100 and the heat source
device HD, heat flowing between the two devices must travel along a
small thermal path. Moreover, the interface IF between the noted
film regions AF, BF preferably is adjacent to (e.g., at) the
contact locations (which can be lines, points, or other localized
areas of contact) CL between the two devices HD, 100. As a result,
heat flowing from the heat source device HD to the thermoelectric
device 100 passes through the film interface IF and creates a hot
side T.sub.h adjacent to (e.g., at) that interface. Reference is
made to FIG. 7.
[0052] As is perhaps best seen in FIG. 6, thermal insulation spaces
TES preferably are defined between the lowland features V of the
thermoelectric device 100 and the rear surface HS of the heat
source device HD, which in some case is a photovoltaic device SC.
These thermal insulation spaces TES, for example, can simply be air
gaps between the two devices HD, 100. If desired, it may be
possible to evacuate these spaces or fill them with an insulative
gas, but doing so is by no means required.
[0053] Referring to FIG. 7, the illustrated peak P is characterized
by a generally triangular, mountain-like configuration in cross
section. As noted above, however, other peak configurations can be
used.
[0054] Thus, in certain embodiments, adjacent to each peak ridge
there preferably is an interface of two different film regions AF,
BF, optionally in combination with there being an interface of two
different film regions AF, BF adjacent to each valley bottom.
[0055] In the exemplary embodiment of FIG. 5, the two film regions
AF, BF may each be a single layer of material. Alternatively, one
or both such film regions may comprise multiple layers of material,
e.g., multiple layers of different material. Additionally or
alternatively, a given film region AF, BF may be applied in a
single operation, or multiple operations may be carried to deposit
such a film region. For example, certain embodiments provide a
deposition method comprising a sequence of depositions including: a
first A-film deposition from a first angle, followed by a first
B-film deposition from a second angle, followed by a second A-film
deposition from the first angle, followed by a second B-film
deposition from the second angle. Such alternating deposition steps
may be repeated more or less times.
[0056] Insofar as the photovoltaic device SC is concerned, it is
contemplated that virtually any known solar cell type may be used.
Commonly, the photovoltaic device will comprise a front electrode
FE, a rear electrode RE, and a photovoltaic film 50 between those
electrodes. The photovoltaic film 50 may in some cases comprise two
semiconductor films 52, 54 (e.g., one p-type semiconductor layer,
and one n-type semiconductor layer) defining between them a
junction. Radiation incident upon the semiconductors creates
electron-hole pairs, and charge carriers migrate across the
junction in opposite directions, so that an electrical charge
results. An electrical current is then obtained in an external
electrical circuit by forming ohmic contacts to the front and rear
electrodes. The production and wiring of solar cells are well known
to people skilled in the field of photovoltaics. Suitable solar
cells are commercially available from a variety of well known
suppliers. In addition, useful solar cells can be manufactured
using various well known methods for producing photovoltaic
devices.
[0057] While some preferred embodiments of the invention have been
described, it should be understood that various changes,
adaptations and modifications may be made therein without departing
from the spirit of the invention and the scope of the appended
claims.
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