U.S. patent application number 12/195538 was filed with the patent office on 2009-02-05 for thermoelectric conversion module and method for manufacturing the same.
This patent application is currently assigned to MURATA MANUFACTURING CO., LTD.. Invention is credited to Yasuhiro Kawauchi, Takanori Nakamura.
Application Number | 20090032080 12/195538 |
Document ID | / |
Family ID | 37801369 |
Filed Date | 2009-02-05 |
United States Patent
Application |
20090032080 |
Kind Code |
A1 |
Kawauchi; Yasuhiro ; et
al. |
February 5, 2009 |
THERMOELECTRIC CONVERSION MODULE AND METHOD FOR MANUFACTURING THE
SAME
Abstract
A compact, high-performance thermoelectric conversion module
includes a laminate having a plurality of insulating layers, p-type
thermoelectric semiconductors and n-type thermoelectric
semiconductors formed by a technique for manufacturing a multilayer
circuit board, particularly a technique for forming a
via-conductor. Pairs of the p-type thermoelectric semiconductors
and the n-type thermoelectric semiconductors are electrically
connected to each other in series through p-n connection conductors
to define thermoelectric conversion element pairs. The
thermoelectric conversion element pairs are connected in series
through, for example, series wiring conductors. The thermoelectric
semiconductors each have a plurality of portions in which the peak
temperatures of thermoelectric figures of merit are different from
each other. These portions are distributed in the stacking
direction of the laminate.
Inventors: |
Kawauchi; Yasuhiro;
(Nagaokakyo-shi, JP) ; Nakamura; Takanori;
(Omihachiman-shi, JP) |
Correspondence
Address: |
MURATA MANUFACTURING COMPANY, LTD.;C/O KEATING & BENNETT, LLP
1800 Alexander Bell Drive, SUITE 200
Reston
VA
20191
US
|
Assignee: |
MURATA MANUFACTURING CO.,
LTD.
Nagaokakyo-shi
JP
|
Family ID: |
37801369 |
Appl. No.: |
12/195538 |
Filed: |
August 21, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2006/318116 |
Sep 13, 2006 |
|
|
|
12195538 |
|
|
|
|
Current U.S.
Class: |
136/224 ;
136/200; 257/E21.001; 438/54 |
Current CPC
Class: |
H01L 35/34 20130101;
H05K 1/0206 20130101; H01L 35/32 20130101; H05K 3/4611 20130101;
H05K 3/4629 20130101; H05K 1/0306 20130101; H05K 2201/10219
20130101 |
Class at
Publication: |
136/224 ;
136/200; 438/54; 257/E21.001 |
International
Class: |
H01L 35/02 20060101
H01L035/02; H01L 21/00 20060101 H01L021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 22, 2006 |
JP |
2006-044912 |
Claims
1. A thermoelectric conversion module comprising: a p-type
thermoelectric semiconductor; an n-type thermoelectric
semiconductor; and a laminate including a plurality of insulating
layers which are electrically insulative and which are stacked;
wherein the laminate has at least one first accommodation hole
accommodating the p-type thermoelectric semiconductor, at least one
second accommodation hole accommodating the n-type thermoelectric
semiconductor, and a p-n connection conductor that electrically
connects the p-type and n-type thermoelectric semiconductors to
each other in series such that the p-type and n-type thermoelectric
semiconductors define a thermoelectric conversion element pair; the
first accommodation hole is defined by a plurality of first
perforations which are communicatively connected to each other and
which extend through the insulating layers in the thickness
direction of the insulating layers; the second accommodation hole
is defined by a plurality of second perforations which are
communicatively connected to each other and which extend through
the insulating layers in the thickness direction of the insulating
layers; at least one of the p-type and n-type thermoelectric
semiconductors includes a plurality of portions in which the peak
temperatures of thermoelectric figures of merit are different from
each other; and the portions are distributed in a stacking
direction of the laminate.
2. The thermoelectric conversion module according to claim 1,
wherein both of the p-type and n-type thermoelectric semiconductors
include the portions in which the peak temperatures of
thermoelectric figures of merit are different from each other.
3. The thermoelectric conversion module according to claim 1,
wherein the laminate includes a plurality of thermoelectric
conversion element pairs.
4. The thermoelectric conversion module according to claim 3,
wherein the laminate includes a plurality of series wiring
conductors arranged to connect the thermoelectric conversion
element pairs in series.
5. The thermoelectric conversion module according to claim 3,
wherein the laminate includes a plurality of parallel wiring
conductors arranged to connect the thermoelectric conversion
element pairs in parallel.
6. A method for manufacturing a thermoelectric conversion module
that includes a p-type thermoelectric semiconductor, an n-type
thermoelectric semiconductor, and a laminate including a plurality
of insulating layers which are electrically insulative and which
are stacked, the laminate having at least one first accommodation
hole accommodating the p-type thermoelectric semiconductor, at
least one second accommodation hole accommodating the n-type
thermoelectric semiconductor, and a p-n connection conductor which
electrically connects the p-type and n-type thermoelectric
semiconductors to each other in series such that the p-type and
n-type thermoelectric semiconductors define a thermoelectric
conversion element pair, the first accommodation hole being defined
by a plurality of first perforations which are communicatively
connected to each other and which extend through the insulating
layers in the thickness direction of the insulating layers, the
second accommodation hole being defined by a plurality of second
perforations which are communicatively connected to each other and
which extend through the insulating layers in the thickness
direction of the insulating layers, the method comprising: a step
of preparing a plurality of insulating sheets for forming the
insulating layers; a step of preparing a p-type thermoelectric
semiconductor material for forming the p-type thermoelectric
semiconductor and an n-type thermoelectric semiconductor material
for forming the n-type thermoelectric semiconductor; a step of
forming the first and second perforations in the insulating sheets;
a step of packing the p-type thermoelectric semiconductor material
and the n-type thermoelectric semiconductor material into the first
perforation and the second perforation, respectively; a step of
forming the p-n connection conductor on specific one of the
insulating sheets; and a step of stacking the insulating sheets
such that the laminate is obtained.
7. The thermoelectric conversion module-manufacturing method
according to claim 6, wherein a step of preparing the p-type
thermoelectric semiconductor material and the n-type thermoelectric
semiconductor material includes a sub-step of preparing different
types of thermoelectric semiconductor components for producing at
least one of the p-type and n-type thermoelectric semiconductor
materials such that the thermoelectric semiconductor includes a
plurality of portions in which the peak temperatures of
thermoelectric figures of merit are different from each other, the
packing step includes a sub-step of packing the different types of
thermoelectric semiconductor components into the perforations of
the insulating sheets, and the stacking step includes a sub-step of
stacking the insulating sheets having the perforations filled with
the different types of thermoelectric semiconductor components such
that the insulating sheets are arranged in the laminate in a mixed
manner.
8. The thermoelectric conversion module-manufacturing method
according to claim 6, further comprising a step of forming series
wiring conductors on a specific one of the insulating sheets,
wherein the laminate includes the series wiring conductors and a
plurality of thermoelectric conversion element pairs connected to
each other in series through the series wiring conductors.
9. The thermoelectric conversion module-manufacturing method
according to claim 6, further comprising a step of forming parallel
wiring conductors on a specific one of the insulating sheets,
wherein the laminate includes the parallel wiring conductors and a
plurality of thermoelectric conversion element pairs connected to
each other in parallel through the parallel wiring conductors.
10. The thermoelectric conversion module-manufacturing method
according to claim 6, further comprising a step of firing the
laminate, the firing step being subsequent to the stacking step,
wherein the insulating sheets are green ceramic sheets.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a thermoelectric conversion
module and a method for manufacturing the thermoelectric conversion
module, and more particularly, to an improvement in a method for
manufacturing a compact, high-performance thermoelectric conversion
module.
[0003] 2. Description of the Related Art
[0004] Conventional techniques relating to the present invention
are disclosed in Japanese Unexamined Patent Application Publication
No. 8-153899 and Japanese Unexamined Patent Application Publication
No. 8-222770.
[0005] Japanese Unexamined Patent Application Publication No.
8-153899 discloses a thermoelectric conversion module including an
insulating frame having a plurality of through-holes spaced from
each other. The through-holes contain p-type or n-type compound
semiconductor elements. The through-holes containing the p-type
compound semiconductor elements and the through-holes containing
the n-type compound semiconductor elements are alternately
arranged. Electrodes are arranged on the upper and lower surfaces
of the frame so as to electrically connect pairs of the p-type and
n-type compound semiconductor elements to each other in series. As
disclosed in Japanese Unexamined Patent Application Publication No.
8-153899, the frame is made of glass or ceramic.
[0006] In the thermoelectric conversion module disclosed in
Japanese Unexamined Patent Application Publication No. 8-153899,
the p-type and n-type compound semiconductor elements are each made
of one type of compound semiconductor material. That is, one
through-hole contains one type of compound semiconductor material.
Therefore, the thermoelectric figure of merit of each element peaks
at one temperature, that is, the element has a single conversion
peak. Thus, the element has relatively low thermoelectric
conversion efficiency.
[0007] Japanese Unexamined Patent Application Publication No.
8-222770 discloses a method for manufacturing a thermoelectric
conversion module. The method includes a step of preparing n-type
laminates such that tabular n-type thermoelectric semiconductors
and tabular insulators are alternately stacked and the stack is cut
substantially perpendicularly to the lamination plane, a step of
preparing p-type laminates such that tabular p-type thermoelectric
semiconductors and tabular insulators are alternately stacked and
the stack is cut substantially perpendicularly to the lamination
plane, a step of alternately stacking the n-type laminates and the
p-type laminates such that the insulators are sandwiched between
the n-type and p-type laminates, and a step of forming wiring
conductors connecting the n-type thermoelectric semiconductors to
the p-type thermoelectric semiconductors adjacent thereto in
series. As disclosed in Japanese Unexamined Patent Application
Publication No. 8-222770, the insulators are made of an epoxy
resin.
[0008] According to the method disclosed in Japanese Unexamined
Patent Application Publication No. 8-222770, the n-type and p-type
laminates are likely to be misaligned with each other in the step
of alternately stacking the n-type and p-type laminates. This
prevents the thermoelectric semiconductors and the wiring
conductors from being properly electrically connected to each
other. Therefore, the thermoelectric semiconductors and the wiring
conductors may be electrically disconnected from each other or
short-circuited.
SUMMARY OF THE INVENTION
[0009] To overcome the above-described problems, preferred
embodiments of the present invention provide a thermoelectric
conversion module and a method for manufacturing the thermoelectric
conversion module.
[0010] A thermoelectric conversion module according to a preferred
embodiment of the present invention includes a p-type
thermoelectric semiconductor, an n-type thermoelectric
semiconductor, and a laminate including a plurality of insulating
layers which are electrically insulative and which are stacked.
[0011] The laminate includes at least one first accommodation hole
accommodating the p-type thermoelectric semiconductor, at least one
second accommodation hole accommodating the n-type thermoelectric
semiconductor, and a p-n connection conductor that electrically
connects the p-type and n-type thermoelectric semiconductors to
each other in series such that the p-type and n-type thermoelectric
semiconductors define a thermoelectric conversion element pair.
[0012] The first accommodation hole is defined by a plurality of
first perforations which are communicatively connected to each
other and which extend through the insulating layers in the
thickness direction of the insulating layers and the second
accommodation hole is defined by a plurality of second perforations
which are communicatively connected to each other and which extend
through the insulating layers in the thickness direction of the
insulating layers.
[0013] At least one of the p-type and n-type thermoelectric
semiconductors includes a plurality of portions in which the peak
temperatures of thermoelectric figures of merit are different from
each other and the portions are distributed in the stacking
direction of the laminate.
[0014] Both of the p-type and n-type thermoelectric semiconductors
preferably include the portions in which the peak temperatures of
thermoelectric figures of merit are different from each other.
[0015] The laminate preferably includes a plurality of
thermoelectric conversion element pairs. In this case, the laminate
includes a plurality of series wiring conductors arranged to
connect the thermoelectric conversion element pairs in series or
includes a plurality of parallel wiring conductors arranged to
connect the thermoelectric conversion element pairs in
parallel.
[0016] Another preferred embodiment of the present invention
provides a method for manufacturing a thermoelectric conversion
module that includes a p-type thermoelectric semiconductor, an
n-type thermoelectric semiconductor, and a laminate including a
plurality of insulating layers which are electrically insulative
and which are stacked. The laminate has at least one first
accommodation hole accommodating the p-type thermoelectric
semiconductor, at least one second accommodation hole accommodating
the n-type thermoelectric semiconductor, and a p-n connection
conductor which electrically connects the p-type and n-type
thermoelectric semiconductors to each other in series such that the
p-type and n-type thermoelectric semiconductors define a
thermoelectric conversion element pair. The first accommodation
hole is defined by a plurality of first perforations which are
communicatively connected to each other and which extend through
the insulating layers in the thickness direction of the insulating
layers. The second accommodation hole is defined by a plurality of
second perforations which are communicatively connected to each
other and which extend through the insulating layers in the
thickness direction of the insulating layers.
[0017] The thermoelectric conversion module-manufacturing method
according to this preferred embodiment of the present invention
includes a step of preparing a plurality of insulating sheets for
forming the insulating layers, a step of preparing a p-type
thermoelectric semiconductor material for forming the p-type
thermoelectric semiconductor and an n-type thermoelectric
semiconductor material for forming the n-type thermoelectric
semiconductor, a step of forming the first and second perforations
in the insulating sheets, a step of packing the p-type
thermoelectric semiconductor material and the n-type thermoelectric
semiconductor material into the first perforation and the second
perforation, respectively, a step of forming the p-n connection
conductor on a specific one of the insulating sheets, and a step of
stacking the insulating sheets such that the laminate is
obtained.
[0018] A thermoelectric conversion module manufactured by the
method according to preferred embodiments of the present invention
is not limited to the above-described thermoelectric conversion
module according to the present invention. The method according to
preferred embodiments of the present invention can be used to
manufacture a thermoelectric conversion module that does not have
the above-mentioned configuration in which at least one of the
p-type and n-type thermoelectric semiconductors includes a
plurality of portions in which the peak temperatures of
thermoelectric figures of merit are different from each other.
However, the method according to preferred embodiments of the
present invention is preferably used to manufacture the
thermoelectric conversion module according to preferred embodiments
of the present invention.
[0019] In a preferred embodiment, the semiconductor-preparing step
includes a sub-step of preparing different types of thermoelectric
semiconductor components for producing at least one of the p-type
and n-type thermoelectric semiconductor materials such that the
thermoelectric semiconductor includes a plurality of portions in
which the peak temperatures of thermoelectric figures of merit are
different from each other, the packing step includes a sub-step of
packing the different types of thermoelectric semiconductor
components into the perforations of the insulating sheets, and the
stacking step includes a sub-step of stacking the insulating sheets
having the perforations filled with the different types of
thermoelectric semiconductor components such that the insulating
sheets are arranged in the laminate in a mixed manner.
[0020] When the laminate, which is included in the thermoelectric
conversion module, includes a plurality of thermoelectric
conversion element pairs and series wiring conductors arranged to
connect the series wiring conductors to each other in series, the
method preferably further includes a step of forming the series
wiring conductors on a specific one of the insulating sheets.
[0021] When the laminate, which is included in the thermoelectric
conversion module, includes a plurality of thermoelectric
conversion element pairs and parallel wiring conductors arranged to
connect the series wiring conductors to each other in parallel, the
method preferably further includes a step of forming the parallel
wiring conductors on a specific one of the insulating sheets.
[0022] In the thermoelectric conversion module-manufacturing method
according to a preferred embodiment of the present invention, the
insulating sheets are preferably green ceramic sheets. In this
case, a step of firing the laminate is performed subsequently to
the stacking step.
[0023] Preferably, at least one of a p-type thermoelectric
semiconductor and an n-type thermoelectric semiconductor includes a
plurality of portions in which the peak temperatures of
thermoelectric figures of merit are different from each other and
the portions are distributed in the stacking direction of a
laminate. Thus, a cascade structure can be achieved and high
thermoelectric conversion efficiency can be obtained over a
specific temperature range.
[0024] When both of the p-type thermoelectric semiconductor and the
n-type thermoelectric semiconductor include the portions in which
the peak temperatures of thermoelectric figures of merit are
different from each other, the thermoelectric conversion module has
an improved thermoelectric conversion efficiency.
[0025] When the laminate includes thermoelectric conversion element
pairs, the thermoelectric conversion element pairs can be
electrically connected to each other through wiring conductors
included in the laminate. The thermoelectric conversion module can
be designed with relatively high flexibility. Therefore, the
thermoelectric conversion module can be readily manufactured so as
to have various characteristics. In the case in which the
thermoelectric conversion module is used as a power generator, high
voltage can be obtained by attaching series wiring conductors, for
connecting the thermoelectric conversion element pairs to each
other in series, to the laminate or a large current can be obtained
by attaching parallel wiring conductors, for connecting the
thermoelectric conversion element pairs to each other in parallel,
to the laminate.
[0026] A method for manufacturing the thermoelectric conversion
module according to preferred embodiments of the present invention
includes steps substantially identical to those of a method for
manufacturing a multilayer circuit board. The laminate, which is
included in the thermoelectric conversion module, corresponds to
the multilayer circuit board, the thermoelectric semiconductors
correspond to via-conductors, and a p-n connection conductor and
the series and parallel wiring conductors correspond to conductive
layers disposed between insulating layers included in a multilayer
circuit board.
[0027] The thermoelectric conversion module-manufacturing method
enables the thermoelectric semiconductors, which correspond to such
via-conductors, to be densely arranged in the laminate. Therefore,
the thermoelectric conversion module can be readily manufactured so
as to have a small size and high performance.
[0028] The wiring conductors and the thermoelectric conversion
element pairs, as well as the multilayer circuit board, can be
flexibly designed. Thus, the thermoelectric conversion module can
be readily manufactured so as to have desired characteristics.
[0029] According to the thermoelectric conversion
module-manufacturing method, the thermoelectric semiconductors are
formed such that the perforations are formed in the insulating
sheets, the thermoelectric semiconductor material is packed into
the perforations, and the insulating sheets are then stacked.
Therefore, one of the thermoelectric semiconductors is not
misaligned with another one thereof. This enables the
thermoelectric conversion module to be protected from electrical
faults or short circuits.
[0030] Where the manufacturing method according to preferred
embodiments of the present invention is used to manufacture a
thermoelectric conversion module in which thermoelectric
semiconductors include portions in which the peak temperatures of
thermoelectric figures of merit are different from each other and
the portions are distributed in the stacking direction of a
laminate, this thermoelectric conversion module can be readily
manufactured such that different types of thermoelectric
semiconductor materials are prepared and then packed into
perforations of other insulating sheets and the insulating sheets
having the perforations filled with the different types of
thermoelectric semiconductor materials are stacked such that the
insulating sheets are arranged in the laminate in a mixed
manner.
[0031] If the insulating sheets are green ceramic sheets and a step
of firing the laminate is performed subsequently to a stacking step
in the thermoelectric conversion module-manufacturing method
according to preferred embodiments of the present invention, the
thermoelectric conversion module can be manufactured through steps
substantially identical to those of a method for manufacturing a
conventional multilayer ceramic circuit board. The commonality of
manufacturing facilities allows the thermoelectric conversion
module to be manufactured at low cost.
[0032] Other features, elements, steps, characteristics and
advantages of the present invention will become more apparent from
the following detailed description of preferred embodiments of the
present invention with reference to the attached drawings.
BREIF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a plan view of a thermoelectric conversion module
according to a first preferred embodiment of the present
invention.
[0034] FIG. 2 is a sectional view taken along the line S2-S2 of
FIG. 1.
[0035] FIG. 3 is a sectional plan view taken along the line S3 of
FIG. 2.
[0036] FIG. 4 is a sectional plan view taken along the line S4 of
FIG. 2.
[0037] FIG. 5 is a sectional plan view taken along the line S5 of
FIG. 2.
[0038] FIG. 6 is a sectional plan view taken along the line S6 of
FIG. 2.
[0039] FIG. 7 is a sectional plan view taken along the line S7 of
FIG. 2.
[0040] FIG. 8 is a sectional plan view taken along the line S8 of
FIG. 2.
[0041] FIG. 9 is a plan view of a thermoelectric conversion module
according to a second preferred embodiment of the present
invention.
[0042] FIG. 10 is a sectional view taken along the line S11-S11 of
FIG. 9.
[0043] FIG. 11 is a sectional plan view taken along the line S12 of
FIG. 10.
[0044] FIG. 12 is a sectional plan view taken along the line S13 of
FIG. 10.
[0045] FIG. 13 is a sectional plan view taken along the line S14 of
FIG. 10.
[0046] FIG. 14 is a sectional plan view taken along the line of
FIG. 10.
[0047] FIG. 15 is a sectional plan view taken along the line of
FIG. 10.
[0048] FIG. 16 is a sectional plan view taken along the line of
FIG. 10.
[0049] FIG. 17 is a sectional plan view taken along the line S18 of
FIG. 10.
[0050] FIG. 18 is a sectional plan view taken along the line S19 of
FIG. 10.
[0051] FIG. 19 is a plan view of a thermoelectric conversion module
according to a third preferred embodiment of the present invention
and corresponds to FIG. 2 or 10.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0052] FIGS. 1 to 8 illustrate a thermoelectric conversion module 1
according to a first preferred embodiment of the present invention.
FIG. 1 is a plan view of the thermoelectric conversion module 1.
FIG. 2 is a sectional view taken along the line S2-S2 of FIG. 1.
FIGS. 3 to 8 are sectional plan views taken along the lines S3 to
S8, respectively, of FIG. 2.
[0053] The thermoelectric conversion module 1 includes a laminate 3
including a plurality of stacked insulating layers 2 which are
electrically insulative. The insulating layers 2 are made of an
alumina-based material, such as a BaO--Al.sub.2O.sub.3--SiO.sub.2
ceramic material or a ZnO--MgO--Al.sub.2O.sub.3--SiO.sub.2 glass
material, for example. The thermoelectric conversion module 1
further includes a plurality of p-type thermoelectric
semiconductors 4 and n-type thermoelectric semiconductors 5
arranged in the laminate 3. The p-type thermoelectric
semiconductors 4 are made of, for example, Chromel. The n-type
thermoelectric semiconductors 5 are made of, for example,
Constantan. The p-type thermoelectric semiconductors 4 and the
n-type thermoelectric semiconductors 5 are alternately arranged in
vertical and horizontal directions as shown in FIGS. 2 and 5 to
7.
[0054] The laminate 3 has a plurality of first accommodation holes
6 accommodating the p-type thermoelectric semiconductors 4 and a
plurality of second accommodation holes 7 accommodating the n-type
thermoelectric semiconductors 5. The first accommodation holes 6
are each defined by a plurality of first perforations 8 extending
through some of the insulating layers 2 in the thickness direction
thereof. The second accommodation holes 7 are each defined by a
plurality of second perforations 9 extending through some of the
insulating layers 2 in the thickness direction thereof.
[0055] The laminate 3 includes p-n connection conductors 11 that
electrically connecting pairs of the p-type thermoelectric
semiconductors 4 and n-type thermoelectric semiconductors 5 to each
other in series such that each p-type thermoelectric semiconductor
4 and n-type thermoelectric semiconductor 5 define a thermoelectric
conversion element pair 10. The p-n connection conductors 11 are
arranged on the outer surface of one of the outermost insulating
layers 2 of the laminate 3 as shown in FIGS. 2 and 8.
[0056] In this preferred embodiment, the thermoelectric conversion
element pairs 10 are connected to each other in series such that a
high voltage is obtained. The laminate 3 further includes a
plurality of series wiring conductors 12 arranged to sequentially
connect the thermoelectric conversion element pairs 10 to each
other in series. The series wiring conductors 12 are arranged on
the outer surface of the other one of the outermost insulating
layers 2 of the laminate 3 as shown in FIGS. 2 and 4.
[0057] The thermoelectric conversion module 1 further includes a
pair of outer layers 13 and 14 sandwiching the laminate 3. The
outer layers 13 and 14 are in contact with cold and hot junctions
of the thermoelectric semiconductors 4 and 5 and are preferably
made of a material which is electrically insulative and which has
relatively good heat conductivity. The outer layers 13 and 14 are
made of, for example, the same material as that for forming the
insulating layers 2.
[0058] The thermoelectric conversion module 1 further includes
extraction conductive layers 15 and 16, extraction via-conductors
17 and 18, and terminal electrodes 19 and 20 for extracting
electricity from the thermoelectric conversion element pairs 10,
which are connected to each other in series. The extraction
conductive layers 15 and 16, as well as the p-n connection
conductors 11, are arranged on the outer surface of one of the
outermost insulating layers 2 of the laminate 3 as shown in FIGS. 2
and 8. The extraction via-conductors 17 and 18 are electrically
connected to the extraction conductive layers 15 and 16,
respectively, extend through the laminate 3 and the outer layer 13,
and are electrically connected to the terminal electrodes 19 and
20, respectively. The terminal electrodes 19 and 20 are arranged on
the outer surface of the outer layer 13.
[0059] The following members are made of a conductive material
including a conductive component, such as Cu, for example: the
extraction conductive layers 15 and 16, the extraction
via-conductors 17 and 18, the terminal electrodes 19 and 20, the
p-n connection conductors 11, and the series wiring conductors
12.
[0060] In the thermoelectric conversion module 1, the p-type
thermoelectric semiconductors 4 and the n-type thermoelectric
semiconductors 5 include a plurality of portions in which the peak
temperatures of thermoelectric figures of merit are different from
each other. In the present application, "peak temperature of
thermoelectric figure of merit" means the temperature at which the
thermoelectric figure of merit has the greatest value. In
particular, the p-type thermoelectric semiconductors 4 include
low-peak temperature portions 21 having a relatively low peak
temperature, medium-peak temperature portions 22 having a medium
peak temperature, and high-peak temperature portions 23 having a
relatively high peak temperature. The n-type thermoelectric
semiconductors 5 include low-peak temperature portions 24 having a
relatively low peak temperature, medium-peak temperature portions
25 having a medium peak temperature, and high-peak temperature
portions 26 having a relatively high peak temperature. As shown in
FIG. 5, the low-peak temperature portions 21 and 24 appear at the
cutting plane S5 of FIG. 2. As shown in FIG. 6, the medium-peak
temperature portions 22 and 25 appear at the cutting plane S6 of
FIG. 2. As shown in FIG. 7, the high-peak temperature portions 23
and 26 appear at the cutting plane S7 of FIG. 2. As is clear from
this configuration, the portions 21 to 23 and 24 to 26 are
distributed in the stacking direction of the laminate 3.
[0061] The low-peak temperature portions 21 and 24, the medium-peak
temperature portions 22 and 25, and the high-peak temperature
portions 23 and 26 may be varied in the order of arrangement,
thickness (size measured in the stacking direction), and/or other
features thereof.
[0062] Since the thermoelectric semiconductors 4 and 5 have a
cascade structure including the portions 21 to 23 and 24 to 26, in
which the peak temperatures of thermoelectric figures of merit are
different from each other, the thermoelectric conversion module 1
has outstanding thermoelectric conversion efficiency over a
specific temperature range.
[0063] A preferable method for manufacturing the thermoelectric
conversion module 1 will now be described.
[0064] A plurality of insulating sheets for forming the insulating
layers 2 are prepared. The insulating sheets are preferably green
ceramic sheets including a BaO--Al.sub.2O.sub.3--SiO.sub.2 ceramic
material. The first and second perforations 8 and 9 are formed in
the insulating sheets using, for example, a laser. Other insulating
sheets, having the same composition as that of those insulating
sheets, for forming the outer layers 13 and 14 are prepared.
[0065] The following materials are prepared: p-type thermoelectric
semiconductor materials for forming the p-type thermoelectric
semiconductors 4 and n-type thermoelectric semiconductor materials
for forming the n-type thermoelectric semiconductors 5. Each p-type
thermoelectric semiconductor material is prepared such that a
Chromel powder and an organic vehicle are mixed into a paste. Each
n-type thermoelectric semiconductor material is prepared such that
a Constantan powder and an organic vehicle are mixed into a paste.
The p-type and n-type thermoelectric semiconductor materials have
thermoelectric figures of merit of which the peak temperatures are
different from each other. The p-type thermoelectric semiconductor
materials are classified into three types: one for the low-peak
temperature portions 21, another one for the medium-peak
temperature portions 22, and the other one for the high-peak
temperature portions 23. The n-type thermoelectric semiconductor
materials are classified into three types: one for the low-peak
temperature portions 24, another one for the medium-peak
temperature portions 25, and the other one for the high-peak
temperature portions 26.
[0066] The p-type thermoelectric semiconductor materials and the
n-type thermoelectric semiconductor materials are packed into the
first perforations 8 and the second perforations 9, respectively.
In this step, the p-type thermoelectric semiconductor materials are
packed into the first perforations 8 such that the second
perforations 9 are masked. The n-type thermoelectric semiconductor
materials are then packed into the second perforations 9 such that
the first perforations 8 are masked. In this step, a screen
printing process is preferably used because perforations other than
perforations to be filled with thermoelectric semiconductor
materials are masked and therefore no masking member or masking
step is required. In the packing step, the three types of
thermoelectric semiconductor materials corresponding to the
low-peak, medium-peak, and high-peak temperature portions 21, 22,
and 23 or the low-peak, medium-peak, and high-peak temperature
portions 24, 25, and 26 are packed into perforations 8 or 9,
respectively, formed in other insulating sheets.
[0067] Through-holes for forming the extraction via-conductors 17
and 18 are formed in the insulating sheets. A conductive paste
including Cu is packed into the through-holes.
[0068] The p-n connection conductors 11 and the extraction
conductive layers 15 and 16 are formed on a specific one of the
insulating sheets. The series wiring conductors 12 are formed on
another specific one of the insulating sheets. The p-n connection
conductors 11, the series wiring conductors 12, and the extraction
conductive layers 15 and 16 are formed by a screen printing process
using a conductive paste including Cu.
[0069] Portions of the extraction via-conductors 17 and 18 are
formed in one of the insulating sheets and the terminal electrodes
19 and 20 are formed on this insulating sheet. The terminal
electrodes 19 and 20 may be formed subsequently to a firing step
below.
[0070] In order to prepare the laminate 3, the insulating sheets
for forming the insulating layers 2 are stacked, the insulating
sheets for forming the outer layers 13 and 14 are deposited on the
stack and then pressed, and the compact is cut as required and then
fired. As a result of firing, the insulating sheets are sintered
into the insulating layers 2 and the outer layers 13 and 14, the
p-type and n-type thermoelectric semiconductor materials are
sintered into the p-type and n-type thermoelectric semiconductors 4
and 5, respectively, and the p-n connection conductors 11, the
series wiring conductors 12, the extraction conductive layers 15
and 16, and the extraction via-conductors 17 and 18 are sintered,
whereby the thermoelectric conversion module 1 is completed.
[0071] In the above stacking step, the insulating sheets, which
have the perforations 8 and 9 filled with the three types of
thermoelectric semiconductor materials, are stacked such that the
laminate 3 is formed. Thus, the laminate 3 has a cascade structure
shown in FIG. 2.
[0072] A sample that is substantially identical to the
thermoelectric conversion module 1, shown in FIGS. 1 to 8,
according to the first preferred embodiment was prepared. The
sample included p-type thermoelectric semiconductors 4 made of
Chromel, n-type thermoelectric semiconductors 5 made of Constantan,
a laminate 3 having accommodation holes 6 and 7 with a diameter of
about 200 .mu.m, for example, and thermoelectric conversion element
pairs 10. The laminate 3 had a thickness of about 300 .mu.m, for
example, before being fired. The thermoelectric semiconductors 4
and 5 were arranged at a pitch of about 400 .mu.m, for example. The
number of the thermoelectric conversion element pairs 10 per one
square centimeter was 228. When a temperature difference of about
205 K was established between a pair of outer plates 13 and 14 such
that one end of each of the thermoelectric semiconductors 4 and 5
was heated with a heater and the other end thereof was cooled with
a fan, an output of about 1.4 W/cm.sup.2 was obtained.
[0073] FIGS. 9 to 18 are illustrations of a thermoelectric
conversion module 31 according to a second preferred embodiment of
the present invention. FIG. 9 is a plan view of the thermoelectric
conversion module 31. FIG. 10 is a sectional view taken along the
line S11-S11 of FIG. 9. FIGS. 11 to 18 are sectional plan views
taken along the lines S12 to S19, respectively, of FIG. 10. In
FIGS. 9 to 18, the same members as those shown in FIGS. 1 to 8 are
denoted by the same reference numerals as those shown in FIGS. 1 to
8 and will not be redundantly described.
[0074] The thermoelectric conversion module 31 according to the
second preferred embodiment includes a plurality of thermoelectric
conversion element pairs 10 that are connected to each other in
parallel. Therefore, a laminate 3 includes parallel wiring
conductors 32 to 37 as shown in FIG. 12 to 14. FIG. 12 shows the
parallel wiring conductive layers 32 and 33, which extend along an
insulating layer 2 and function as parallel wiring conductors. FIG.
13 shows the parallel wiring via-conductors 34 and 35, which extend
in the thickness direction of an insulating layer 2 and function as
parallel wiring conductors. FIG. 14 shows the parallel wiring
conductive layers 36 and 37, which extend along an insulating layer
2 and function as parallel wiring conductors.
[0075] As is clear from the comparison of FIGS. 15 to 17 with FIG.
18, p-type thermoelectric semiconductors 4 and n-type
thermoelectric semiconductors 5, as well as those described in the
first preferred embodiment, form pairs and are electrically
connected to each other in series through p-n connection conductors
11. These members define the thermoelectric conversion element
pairs 10.
[0076] As is clear from the comparison of FIG. 14 with FIGS. 15 to
17, end portions of the thermoelectric conversion element pairs 10
that are arranged in the vertical direction in FIGS. 15 to 17 are
connected to each other in parallel through the parallel wiring
conductive layers 36 or 37. One of the parallel wiring conductive
layers 36 is connected to one end portion of each of the
thermoelectric conversion element pairs 10 and one of the parallel
wiring conductive layers 37 is connected to the other end portion
thereof. The parallel wiring conductive layers 36 and 37 are
alternately arranged.
[0077] With reference to FIGS. 12 to 14, the parallel wiring
conductive layers 36, which define a group, are connected to the
parallel wiring conductive layer 32 through the parallel wiring
via-conductors 34 and the parallel wiring conductive layers 37,
which define another group, are connected to the parallel wiring
conductive layer 33 through the parallel wiring via-conductors
35.
[0078] With reference to FIG. 11, extraction via-conductors 38 and
39 extend through an outer layer 13 in the thickness direction
thereof. Terminal electrodes 40 and 41 are arranged on the outer
surface of the outer layer 13. Therefore, as is clear from FIGS. 9,
11, and 12, the terminal electrode 40 is connected to the parallel
wiring conductive layer 32 through the extraction via-conductor 38
and the terminal electrode 41 is connected to the parallel wiring
conductive layer 33 through the extraction via-conductor 39.
[0079] The thermoelectric conversion module 31 has a configuration
in which the thermoelectric conversion element pairs 10, which are
connected to each other in parallel, are arranged between a pair of
the terminal electrodes 40 and 41.
[0080] The thermoelectric conversion module 31 can be manufactured
by substantially the same method as that for manufacturing the
above-described thermoelectric conversion module 1 except that the
following step is performed: a step of forming the parallel wiring
conductive layers 32 and 33, the parallel wiring via-conductors 34
and 35, and the parallel wiring conductive layers 36 and 37 on
specific insulating sheets.
[0081] FIG. 19 is a sectional view of a thermoelectric conversion
module 51 according to a third preferred embodiment of the present
invention and corresponds to FIG. 2 or 10. In FIG. 19, the same
members as those shown in FIG. 2 or 10 are denoted by the same
reference numerals as those shown in FIG. 2 or 10 and will not be
redundantly described.
[0082] The thermoelectric conversion module 51 according to the
third preferred embodiment has a configuration in which a plurality
of structures identical to the thermoelectric conversion module 1,
shown in FIG. 2, including the thermoelectric conversion element
pairs 10 connected to each other in series are connected to each
other in parallel.
[0083] In particular, the structures, which correspond to the
thermoelectric conversion module 1 shown in FIG. 2, each include
extraction via-conductors 17 and 18 (the extraction via-conductors
17 not being shown in FIG. 19). The extraction via-conductors 17
and 18 are connected to each other, whereby the structures, which
correspond to the thermoelectric conversion module 1 shown in FIG.
2, are electrically connected to each other in parallel.
[0084] The number of structures, which are included in the
thermoelectric conversion module 51 shown in FIG. 19 and correspond
to the thermoelectric conversion module 1 shown in FIG. 2, is two,
and may, alternatively, be three or more as required.
[0085] A thermoelectric conversion module according to of the
present invention is as described above with reference to the
preferred embodiments and various modifications may be made.
[0086] When a thermoelectric conversion module includes a plurality
of thermoelectric conversion element pairs, the thermoelectric
conversion element pairs may be connected to each other by various
techniques other than those described with reference to the
foregoing figures. The number of the thermoelectric conversion
element pairs may be arbitrarily varied. The present invention
covers a thermoelectric conversion module including a single
thermoelectric conversion element pair.
[0087] In the above preferred embodiments described with reference
to the foregoing figures, the p-type and n-type thermoelectric
semiconductors 4 and 5 each include the three portions in which the
peak temperatures of thermoelectric figures of merit are different
from each other. The number of such portions in which the peak
temperatures of thermoelectric figures of merit are different from
each other may be arbitrarily varied. Only the p-type or n-type
thermoelectric semiconductors 4 or 5 may include such portions in
which the peak temperatures of thermoelectric figures of merit are
different from each other.
[0088] In the above preferred embodiments described with reference
to the foregoing figures, the portions in which the peak
temperatures of thermoelectric figures of merit are different from
each other are arranged in the p-type and n-type thermoelectric
semiconductors 4 and 5 in the same manner. In other words, if one
of the insulating layers 2 arranged in the laminate 3 is examined,
portions of the p-type and n-type thermoelectric semiconductors 4
and 5 in which the peak temperatures of thermoelectric figures of
merit are the same are disposed in the perforations 8 and 9. The
p-type or n-type thermoelectric semiconductors may include portions
in which the peak temperatures of thermoelectric figures of merit
are different from each other and which are disposed in a plurality
of perforations.
[0089] In order to reduce the thermal stress applied to a
thermoelectric conversion module, thermoelectric semiconductors
and/or insulating sheets may be made of different materials or may
have portions made of material having different thermal expansion
coefficients. A material for forming the insulating sheets is not
limited to ceramic or glass and a resin may be used to form the
insulating sheets.
[0090] While preferred embodiments of the present invention have
been described above, it is to be understood that variations and
modifications will be apparent to those skilled in the art without
departing the scope and spirit of the present invention. The scope
of the present invention, therefore, is to be determined solely by
the following claims.
* * * * *