U.S. patent application number 12/403674 was filed with the patent office on 2009-09-24 for heat exchange device.
This patent application is currently assigned to YAMAHA CORPORATION. Invention is credited to YUMA HORIO.
Application Number | 20090236087 12/403674 |
Document ID | / |
Family ID | 41087741 |
Filed Date | 2009-09-24 |
United States Patent
Application |
20090236087 |
Kind Code |
A1 |
HORIO; YUMA |
September 24, 2009 |
HEAT EXCHANGE DEVICE
Abstract
A heat exchange device includes a heat exchanger disposed in
connection with at least one of a heat-dissipation electrode and a
heat-absorption electrode, between which a plurality of
thermoelectric elements is connected in series, via an insulating
resin layer, which is composed of an epoxy resin or polyimide resin
doped with fillers having high thermal conductivity, without
intervention of a substrate. The heat exchanger corresponds to a
plurality of corrugated fins which are constituted of a plurality
of joint regions joining with one of the heat-dissipation electrode
and heat-absorption electrode and a plurality of non-joint regions
projecting externally from a plurality of gaps formed between the
joint regions adjacently aligned together, wherein the joint
regions and non-joint regions are alternately aligned. Thus, it is
possible to achieve high reliability by reducing thermal resistance
and thermal stress while increasing the maximum heat absorption
coefficient (Qmax).
Inventors: |
HORIO; YUMA; (Hamamatsu-shi,
JP) |
Correspondence
Address: |
DICKSTEIN SHAPIRO LLP
1633 Broadway
NEW YORK
NY
10019
US
|
Assignee: |
YAMAHA CORPORATION
Hamamatsu-Shi
JP
|
Family ID: |
41087741 |
Appl. No.: |
12/403674 |
Filed: |
March 13, 2009 |
Current U.S.
Class: |
165/185 |
Current CPC
Class: |
H01L 35/30 20130101 |
Class at
Publication: |
165/185 |
International
Class: |
F28F 7/00 20060101
F28F007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 19, 2008 |
JP |
2008-071723 |
Claims
1. A heat exchange device including a heat exchanger and a
thermoelectric module constituted of a plurality of thermoelectric
elements which are connected in series and aligned in connection
with at least one of a heat-dissipation electrode and a
heat-absorption electrode, which is coupled with the heat exchanger
via an insulating resin layer having high thermal conductivity and
an adhesive property, wherein the heat exchanger corresponds to a
plurality of corrugated fins which are constituted of a plurality
of joint regions joining one of the heat-dissipation electrode and
the heat-absorption electrode via the insulating resin layer and a
plurality of non-joint regions projecting externally from a
plurality of gaps formed between the joint regions adjacently
aligned together, and wherein the plurality of joint regions and
the plurality of non-joint regions are alternately aligned in
connection with one of the heat-dissipation electrode and the
heat-absorption electrode.
2. The heat exchange device according to claim 1, wherein a width
of the joint region is larger than a width of the gap formed
between the joint regions adjacently aligned in the corrugated
fins.
3. The heat exchange device according to claim 1, wherein the
insulating resin layer is composed of a polyimide resin or an epoxy
resin.
4. The heat exchange device according to claim 1, wherein the
insulating resin layer is doped with a plurality of fillers having
high thermal conductivity.
5. The heat exchange device according to claim 4, wherein the
fillers are composed of any one of an alumina powder, an aluminum
nitride powder, and a magnesium oxide powder.
6. A heat exchange device comprising: a plurality of
heat-dissipation electrodes which are separated from each other and
are linearly aligned; a plurality of heat-absorption electrodes
which are separated from each other and are linearly aligned; a
plurality of thermoelectric elements which are connected in series
and aligned between the plurality of heat-dissipation electrodes
and the heat-absorption electrodes; and at least one heat exchanger
which is disposed in connection with at least one of the
heat-dissipation electrodes and the heat-absorption electrodes and
which is constituted of a plurality of joint regions joining with
one of the heat-dissipation electrodes and the heat-absorption
electrodes via a plurality of insulating resin layers and a
plurality of non-joint regions projecting externally from a
plurality of gaps formed between the joint regions adjacently
aligned together.
7. The heat exchange device according to claim 6, wherein the
plurality of insulating resin layers is composed of a polyimide
resin or an epoxy resin, which is doped with a plurality of fillers
having high thermal conductivity.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to heat exchange devices
including heat exchangers coupled with thermoelectric modules
having thermoelectric elements connected in series between
heat-dissipation electrodes and heat-absorption electrodes.
[0003] The present application claims priority on Japanese Patent
Application No. 2008-71723, the content of which is incorporated
herein by reference.
[0004] 2. Description of the Related Art
[0005] Conventionally-known thermoelectric modules are designed
such that different types of thermoelectric elements composed of
P-type and N-type semiconductors are alternately aligned and
connected in series between heat-dissipation electrodes and
heat-absorption electrodes via bonding metals such as solders.
Various techniques have been developed to improve heat dissipation
efficiency in thermoelectric modules, wherein heat exchangers are
coupled to heat-dissipation substrates or heat-absorption
substrates so as to form heat exchange devices, for example.
[0006] Various heat exchange devices have been developed and
disclosed in various documents such as Patent Document 1.
[0007] Patent Document 1: Japanese Unexamined Patent Application
Publication No. 2007-93106
[0008] Patent Document 1 teaches a heat exchange device 50 as shown
in FIG. 7 in which a plurality of thermoelectric elements 58 is
aligned between a pair of substrates 51 and 56 which are positioned
opposite to each other. Adjacent thermoelectric elements 58 are
electrically connected together via electrodes 52 and 57 which are
attached to the interior surfaces of the substrates 51 and 56, thus
forming a thermoelectric module 50a. A plurality of corrugated fins
53 is attached to one of the exterior surfaces of the substrates 51
and 56 (e.g. the exterior surface of the substrate 56 in FIG. 7)
via an alloy layer 55 and a bonding material 54, thus forming a
heat exchange device 50.
[0009] The corrugated fins 53 are aligned in connection with a
plurality of joint regions 53a formed on the exterior surface of
the substrate 56, wherein they include heat exchange regions 53b
which are projected from the thermoelectric module 50a and each of
which is disposed to connect between two adjacent joint regions
53a, and wherein the width of each joint region 53a is larger than
the gap between two adjacent joint regions 53a. Thus, it is
possible to achieve high reliability and high heat exchange
performance with a heat exchange device having a simple
structure.
[0010] It is essential for the thermoelectric module 50a of the
heat exchange device 50 to have a pair of substrates 51 and 56
which cause thermal resistance. Hence, the heat exchange device 50
disclosed in Patent Document 1 suffers from degradation of the
maximum heat absorption coefficient (Qmax) which is a significant
factor determining the performance of a thermoelectric module.
[0011] Since the thermoelectric module 50a is designed such that
the thermoelectric elements 58 are aligned in connection with the
substrates 51 and 56 via the electrodes 52 and 57, the
thermoelectric elements 58 must be restricted in positioning
between the substrates 51 and 56. This makes it difficult to
sufficiently release thermal stress from the thermoelectric
elements 58, thus degrading the reliability of the thermoelectric
module 50a against thermal stress.
SUMMARY OF THE INVENTION
[0012] It is an object of the present invention to provide a heat
exchange device which is improved in heat absorption by reducing
thermal resistance and which achieves high reliability by reducing
thermal stress.
[0013] A heat exchange device of the present invention includes a
heat exchanger and a thermoelectric module constituted of a
plurality of thermoelectric elements which are connected in series
and aligned in connection with at least one of a heat-dissipation
electrode and a heat-absorption electrode, which is coupled with
the heat exchanger via an insulating resin layer having high
thermal conductivity and an adhesive property. The heat exchanger
corresponds to a plurality of corrugated fins which are constituted
of a plurality of joint regions joining with one of the
heat-dissipation electrode and heat-absorption electrode via the
insulating resin layer and a plurality of non-joint regions
projecting externally from a plurality of gaps formed between the
joint regions adjacently aligned together, wherein the joint
regions and non-joint regions are alternately aligned in connection
with one of the heat-dissipation electrode and heat-absorption
electrode.
[0014] Since one of the heat-dissipation electrode and
heat-absorption electrode is not equipped with a substrate and is
thus reduced in thermal resistance, it is possible to increase the
maximum heat absorption coefficient (Qmax). The thermoelectric
elements are bonded via the insulating resin layer so as to support
one of the heat-dissipation electrode and heat-absorption
electrode, thus eliminating the necessity of a substrate.
[0015] Thermal stress occurring in the corrugated fins is absorbed
by the non-joint regions aligned in the gaps between adjacent joint
regions, thus improving reliability against thermal stress. By
completely eliminating the necessity of a substrate with respect to
both of the heat-dissipation electrode and heat-absorption
electrode, it is possible to further reduce thermal resistance,
thus further increasing the maximum heat absorption coefficient
(Qmax).
[0016] Since the width of the joint region is larger than the width
of the gap formed between adjacent joint regions, it is possible to
efficiently transmit heat generated by the thermoelectric elements
to the corrugated fins, thus improving heat exchange efficiency. It
is preferable that the insulating resin layer be composed of a
polyimide resin or epoxy resin which is doped with fillers having
high thermal conductivity such as alumina powder, aluminum nitride
powder, and magnesium oxide powder.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] These and other objects, aspects, and embodiments of the
present invention will be described in more detail with reference
to the following drawings.
[0018] FIG. 1 is a cross-sectional view showing the constitution of
a heat exchange device according to a first embodiment of the
present invention.
[0019] FIG. 2 is a cross-sectional view showing the constitution of
a heat exchange device according to a second embodiment of the
present invention.
[0020] FIG. 3 is a cross-sectional view showing the constitution of
a heat exchange device according to a third embodiment of the
present invention.
[0021] FIG. 4 is a cross-sectional view showing the constitution of
a heat exchange device according to a fourth embodiment of the
present invention.
[0022] FIG. 5A is a plan view showing an alignment of electrodes in
two lines along a joint region of each corrugated fin in the heat
exchange device of FIG. 4.
[0023] FIG. 5B is a cross-sectional view of each corrugated fin
whose joint region is increased in width in conjunction with FIG.
5A.
[0024] FIG. 6A is a plan view showing an alignment of electrodes in
four lines along the joint region of each corrugated fin in a heat
exchange device according to a variation of the fourth
embodiment.
[0025] FIG. 6B is a cross-sectional view of each corrugated fin
whose joint region is further increased in width in conjunction
with FIG. 6A.
[0026] FIG. 7 is a cross-sectional view showing the constitution of
a conventionally-known heat exchange device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] The present invention will be described in further detail by
way of examples with reference to the accompanying drawings.
1. FIRST EMBODIMENT
[0028] FIG. 1 is a cross-sectional view showing the constitution of
a heat exchange device 10 according to a first embodiment of the
present invention. The heat exchange device 10 is constituted of a
substrate 11, a heat-dissipation electrode 12 which is formed below
the substrate 11, a plurality of corrugated fins 13 (collectively
serving as a heat exchanger on a heat-absorption side, a
heat-absorption electrode 15 which is bonded onto the upper
surfaces of the corrugated fins 13 via an insulating resin layer 14
having a high heat conductivity and an adhesive property, and a
plurality of thermoelectric elements 16 which are electrically
connected in series between the electrodes 12 and 15 via a
soldering layer (or a metal) 16a.
[0029] A pair of terminals 15a is formed on one end of the
heat-absorption electrode 15 in order to establish electric
connections with leads 17. A thermoelectric module 10a is
constituted of the heat-dissipation electrode 12, the
heat-absorption electrode 15, and the thermoelectric elements which
are connected together in series between the electrodes 12 and 15
via the metal 16a.
[0030] The substrate 11 has high thermal conductivity (which
preferably ranges from 1 W/mK to 8 W/mK), an adhesive property, and
an electric insulating property, wherein it is composed of a
polyimide resin or epoxy resin with a thickness ranging from 10
.mu.m to 100 .mu.m. Fillers such as powder particles composed of
alumina (Al.sub.2O.sub.3), aluminum nitride (AlN), or magnesium
oxide (MgO) and having an average particle diameter of 15 .mu.m or
less are dispersed and doped in the polyimide resin or epoxy resin
so as to improve its thermal conductivity.
[0031] The heat-dissipation electrode 12 is made of a copper film
or copper alloy film whose thickness ranges from 70 .mu.m to 200
.mu.m. The corrugated fins 13 are composed of copper, a copper
alloy, aluminum, or an aluminum alloy. Each of the corrugated fins
13 is constituted of a joint region 131 joining the insulating
resin layer 14 and a non-joint region 13b which project downwardly
from a gap between adjacent joint regions 13a (i.e. in a direction
opposite to the heat-absorption electrode 15). The width (denoted
by "x") of the joint region 13a is larger than the base width
(denoted by "y") of the non-joint region 13b.
[0032] The insulating resin layer 14 is composed of a prescribed
material having high thermal conductivity (which preferably ranges
from 1 W/mK to 8 W/mK), an adhesive property, and an electric
insulating property such as a polyimide resin or epoxy resin with a
thickness ranging from 10 .mu.m to 100 .mu.m. Fillers such as
powder particles composed of alumina (Al.sub.2O.sub.3), aluminum
nitride (AlN), or magnesium oxide (MgO) and having an average
particle diameter of 15 .mu.m or less are dispersed and doped in
the polyimide resin or epoxy resin so as to improve its thermal
conductivity.
[0033] Similar to the heat-dissipation electrode 12, the
heat-absorption electrode 15 is composed of a copper film or copper
alloy film with a thickness ranging from 70 .mu.m to 200 .mu.m. A
plurality of thermoelectric elements 16 is disposed and connected
in series between the electrodes 12 and 15. The thermoelectric
elements 16 are composed of compounds of N-type and P-type
semiconductors. The thermoelectric elements 16 are electrically
connected in series in the order of P, N, P, N, . . . in such a way
that they are soldered to the electrodes 12 and 15 by use of
soldering materials such as an SnSb alloy, SnAu alloy, and SnAgCu
alloy, thus forming solder layers 16a. In this connection, nickel
plating is adapted to soldered ends of each thermoelectric element
16.
[0034] It is preferable that the thermoelectric element 16 be
formed as sintered body composed of Bi--Te (bismuth-tellurium)
thermoelectric materials which demonstrate high performance at room
temperature. It is preferable that P-type semiconductor compounds
be composed of ternary elements such as Bi--Sb--Te, and N-type
semiconductor compounds be composed of quadruple elements such as
Bi--Sb--Te--Se. Specifically, the composition of P-type
semiconductor compounds is expressed as
Bi.sub.0.5Sb.sub.1.5Te.sub.3 while the composition of N-type
semiconductor compounds is expressed as
Bi.sub.1.9Sb.sub.0.1Te.sub.2.6Se.sub.0.4, wherein both of them are
formed by way of hot-press sintering.
[0035] Since the heat exchange device 10 of the first embodiment is
designed such that the substrate 11 is disposed in connection with
only the heat-dissipation electrode 12, it is possible to reduce
thermal resistance, thus improving the maximum heat absorption
coefficient (Qmax). None of the insulating resin layer 14 and the
heat-absorption electrode 15 is disposed in gaps between adjacent
joint regions 13a among the corrugated fins 13, wherein these gaps
absorb thermal stress. Thus, it is possible to avoid the occurrence
of cracks and defects due to thermal stress in advance, and it is
possible to achieve high reliability in the heat exchange device
10.
[0036] Next, an actual manufacturing method of the heat exchange
device 10 will be described below.
[0037] The substrate 11 composed of an insulating resin such as a
polyimide resin or epoxy resin is fabricated with a thickness
ranging from 10 .mu.m to 100 .mu.m in such a way that the
heat-dissipation electrode 12 is formed on the lower surface
thereof. In addition, the corrugated fins 13 composed of copper, a
copper alloy, aluminum, or an aluminum alloy are fabricated in such
a way that the heat-absorption electrode 15 is attached to each of
the joint regions 13a via the insulating resin layer whose
thickness ranges from 10 .mu.m to 100 .mu.m. Furthermore, the
thermoelectric elements 16 are fabricated using P-type and N-type
semiconductor compounds.
[0038] The heat-dissipation electrode 12 and the heat-absorption
electrode 15 each composed of a copper film or copper alloy film
are each formed with a prescribed thickness (ranging from 70 .mu.m
to 200 .mu.m) and a prescribed electrode pattern by way of DBC
(Direct Bonding Copper), for example. Nickel plating is adapted to
distal ends (opposite ends in the longitudinal direction) of P-type
and N-type semiconductor compounds.
[0039] The thermoelectric elements composed of P-type and N-type
semiconductor compounds are alternately aligned on the
heat-absorption electrodes 15 (composed of a copper film or copper
alloy film) attached to the corrugated fins 13, wherein the
substrate 11 (composed of an insulating resin) having the
heat-dissipation electrode 12 (composed of a copper film or copper
alloy film) is disposed on the thermoelectric elements 16. The
upper ends of the thermoelectric elements 16 (composed of P-type
and N-type semiconductor compounds which are alternately aligned
below the heat-dissipation electrode 12) are soldered to the lower
surface of the heat-dissipation electrode 12 via soldering
materials such as an SnSb alloy, SnAu alloy, and SnAgCu alloy,
while the lower ends of the thermoelectric elements 16 are soldered
to the upper surface of the heat-absorption electrode 15 via
soldering materials such as an SnSb alloy, SnAu alloy, and SnAgCu
alloy.
[0040] Thus, the thermoelectric elements 16 are connected in series
between the heat-dissipation electrode 12 and the heat-absorption
electrode 15 via the solder layers 16a such that the P-type and
N-type semiconductor compounds thereof are alternately aligned.
Thereafter, the leads 17 are soldered to the terminals 15a formed
on one end of the heat-absorption electrode 15. This completes the
production of the heat exchange device 10.
2. SECOND EMBODIMENT
[0041] FIG. 2 is a cross-sectional view showing the constitution of
a heat exchange device 20 according to a second embodiment of the
present invention.
[0042] In contrast to the heat exchange device 10 where the
corrugated fins 13 are arranged on the heat-absorption electrode 15
only, the heat exchange device 20 is designed such that corrugated
fins are arranged on both of the heat-absorption and
heat-dissipation sides. The heat exchange device 20 has a
thermoelectric module 20a which is similar to the thermoelectric
module 10a installed in the heat exchange device 10.
[0043] Specifically, the heat exchange device 20 includes first
corrugated fins 21 (which collectively serve as a heat-dissipation
side heat exchanger), a joint film 22 composed of a copper film or
copper alloy film for entirely covering the lower surfaces of the
first corrugated fins 21, and a heat-dissipation electrode 24 which
is attached to the joint film 22 via an insulating resin layer 23
having high thermal conductivity and an adhesive property which is
adhered to the lower surface of the joint film 22 entirely. In
addition, the heat exchange device 20 includes second corrugated
fins 25 (which collectively serve as a heat-absorption side heat
exchanger) and a heat-absorption electrode 27 which is attached to
the upper surfaces of the second corrugated fins 25 via an
insulating resin layer 26 having high thermal conductivity and an
adhesive property. A plurality of thermoelectric elements 28 is
electrically connected in series and connected between the
electrodes 24 and 27 via solder layers (or metals) 28a, thus
forming the thermoelectric module 20a. A pair of terminals 27a is
formed on one end of the heat-absorption electrode 27 so as to
establish an electrical connection with leads 29.
[0044] Both of the first corrugated fins 21 and the second
corrugated fins 25 are composed of the foregoing materials used for
the corrugated fins 13. The first corrugated fins 21 are
constituted of joint regions 21a and non-joint regions 21b which
project upwardly from gaps between adjacent joint regions 21a,
while the second corrugated fins 25 are constituted of joint
regions 25a and non-joint regions 25b which project downwardly from
gaps between adjacent joint regions 25a. Herein, the width x of the
joint region 21a is larger than the width y of the lower end of the
non-joint region 21b, while the width x of the joint region 25a is
larger than the width y of the upper end of the non-joint region
25b. The joint film 22 composed of a copper film or copper alloy
film is attached to the joint regions 21 a so as to entirely cover
the lower surfaces of the first corrugated fins 21. The insulating
resin layers 23 and 26 are each composed of the foregoing material
used for the insulating resin layer 14; specifically, they are each
composed of a polyimide resin or epoxy resin with a thickness
ranging from 10 .mu.m to 100 .mu.m.
[0045] Fillers such as powder particles composed of alumina
(Al.sub.2O.sub.3), aluminum nitride (AlN), or magnesium oxide (MgO)
and having an average particle diameter of 15 .mu.m or less are
dispersed and doped in the polyimide resin or epoxy resin so as to
improve its thermal conductivity. Similar to the heat-dissipation
electrode 12 and the heat-absorption electrode 15, the
heat-dissipation electrode 24 and the heat-absorption electrode 27
are each composed of a copper film or copper alloy film with a
thickness ranging from 70 .mu.m to 200 .mu.m. A plurality of
thermoelectric elements 28 is electrically connected in series and
connected between the electrodes 24 and 27. The thermoelectric
elements 28 are soldered to the electrodes 24 and 27 via soldering
materials such as an SnSb alloy, SnAu alloy, and SnAgCu alloy, thus
forming the solder layers 28a. The composition of the
thermoelectric elements 28 is identical to the composition of the
thermoelectric elements 16.
[0046] Since the heat exchange device 20 is fabricated without
using the substrate, it is possible to reduce the thermal
resistance, thus improving the maximum heat absorption coefficient
(Qmax). None of the insulating resin layer 26 and the
heat-absorption electrode 27 is disposed in gaps between the joint
regions 25a of the corrugated fins 25, wherein these gaps absorb
thermal stress. Thus, it is possible to avoid the occurrence of
cracks and defects in the thermoelectric elements 28 due to thermal
stress in advance, and it is possible to achieve high reliability
in the heat exchange device 20.
[0047] Next, an actual manufacturing method of the heat exchange
device 20 will be described below.
[0048] The first corrugated fins 21 composed of copper, a copper
alloy, aluminum, or an aluminum alloy are fabricated in such a way
that the joint regions 21a are attached to the joint film 22 so as
to connect with the heat-dissipation electrode 24 via the
insulating resin layer 23 whose thickness ranges from 10 .mu.m to
100 .mu.m. In addition, the second corrugated fins 25 composed of
copper, a copper alloy, aluminum, or an aluminum alloy are
fabricated in such a way that the joint regions 25a are attached to
the heat-absorption electrode 27 via the insulating resin layer 26
whose thickness ranges from 10 .mu.m to 100 .mu.m. Furthermore, the
thermoelectric elements 28 are formed using P-type and N-type
semiconductor compounds.
[0049] The heat-dissipation electrode 24 and the heat-absorption
electrode 27 each composed of a copper film or copper alloy film
are each formed in a prescribed electrode pattern with a thickness
ranging from 70 .mu.m to 200 .mu.m by way of DBC (Direct Bonding
Copper). Nickel plating is adapted to the distal ends (i.e.
opposite ends in the longitudinal direction) of P-type and N-type
semiconductor compounds.
[0050] The thermoelectric elements 28 are arranged on the
heat-absorption electrode 27 (composed of a copper or copper alloy
film) attached to the second corrugated fins 25 such that P-type
and N-type semiconductor compounds are alternately aligned. The
first corrugated fins 21 attached to the heat-dissipation electrode
24 (composed of a copper film or copper alloy film) are disposed
above the thermoelectric elements 28. The upper ends of the
thermoelectric elements 28 (composed of P-type and N-type
semiconductor compounds below the heat-dissipation electrode 24)
are soldered to the lower surface of the heat-dissipation electrode
24 via soldering materials such as an SnSb alloy, SnAu alloy, and
SnAgCu alloy, while the lower ends of the thermoelectric elements
28 are soldered to the upper surface of the heat-absorption
electrode 27 via soldering materials such as an SnSb ally, SnAu
alloy, and SnAgCu alloy.
[0051] The thermoelectric elements 28 are connected in series
between the heat-dissipation electrode 24 and the heat-absorption
electrode 27 via the solder layers 28a such that P-type and N-type
semiconductor compounds thereof are alternately aligned.
Thereafter, the leads 29 are soldered to the terminals 27a on one
end of the heat-absorption electrode 27, thus completing the
production of the heat exchange device 20.
3. THIRD EMBODIMENT
[0052] FIG. 3 is a cross-sectional view showing the constitution of
a heat exchange device 30 according to a third embodiment of the
present invention.
[0053] In the heat exchange device 20, the lower surfaces of the
corrugated fins 21 are entirely covered with the joint film 22, the
lower surface of which is entirely covered with the insulating
resin layer 23; but this is not a restriction. It is possible to
dispose an insulating resin layer in connection with only the joint
regions of corrugated fins without intervention of a joint film.
The heat exchange device 30 is designed to dispose an insulating
resin layer in connection with only the joint regions of corrugated
fins without using a joint film. As shown in FIG. 3, the heat
exchange device 30 has a thermoelectric module 30a similar to the
thermoelectric module 10a installed in the heat exchange device
10.
[0054] Specifically, the heat exchange device 30 includes first
corrugated fins 31 (which collectively serve as a heat-dissipation
side heat exchanger), a heat-dissipation electrode 33 which is
attached below the first corrugated fins 31 via an insulating resin
layer 32 having high thermal conductivity and an adhesive property,
second corrugated fins 34 (which collectively serve as a
heat-absorption side heat exchanger), and a heat-absorption
electrode 36 which is attached above the second corrugated fins via
an insulating resin layer 35 having high thermal conductivity and
an adhesive property. A plurality of thermoelectric elements 37 is
electrically connected in series between the electrodes 33 and 36
via solder layers (or metals) 37a. A pair of terminals 36a is
formed on one end of the heat-absorption electrode 36 so as to
establish an electrical connection with leads 38.
[0055] Both the first corrugated fins 31 and the second corrugated
fins 34 are composed of the foregoing material used for the
corrugated fins 13. The first corrugated fins 31 are constituted of
joint regions 31a and non-joint regions 31b which project upwardly
from gaps between adjacent joint regions 31a, while the second
corrugated fins 34 are constituted of joint regions 34a and
non-joint regions 34b which project downwardly from gaps between
adjacent joint regions 34a. The width x of the joint region 31a is
larger than the width y of the lower end of the non-joint region
31b, while the width x of the joint region 34a is larger than the
width y of the upper end of the non-joint region 34b. Both the
insulating region layers 32 and 35 are composed of the foregoing
material used for the insulating region layer 14; specifically,
they are each composed of a polyimide resin or epoxy resin with a
thickness ranging from 10 .mu.m to 100 .mu.m.
[0056] Fillers such as powder particles composed of alumina
(Al.sub.2O.sub.3), aluminum nitride (AlN), or magnesium oxide (MgO)
and having an average particle diameter of 15 .mu.m or less are
dispersed and doped in the polyimide resin or epoxy resin so as to
improve its thermal conductivity. Similar to the heat-dissipation
electrode 12 and the heat-absorption electrode 15, the
heat-dissipation electrode 33 and the heat-absorption electrode 36
are each composed of a copper film or copper alloy film with a
thickness ranging from 70 .mu.m to 200 .mu.m. A plurality of
thermoelectric elements 37 is electrically connected in series
between the electrodes 33 and 36. The distal ends of the
thermoelectric elements 37 are soldered to the electrodes 33 and 36
via soldering materials such as an SnSb alloy, SnAu alloy, and
SnAgCu alloy, thus forming solder layers 37a. The composition of
the thermoelectric elements 37 is identical to the composition of
the thermoelectric elements 16.
[0057] Since the heat exchange device 30 does not use a substrate,
it is possible to reduce thermal resistance, thus improving the
maximum heat absorption coefficient (Qmax). None of the insulating
resin layers 32 and 35 and the electrodes 33 and 36 is disposed in
gaps between adjacent joint regions 31a and 34a of the corrugated
fins 31 and 34, wherein these gaps absorb thermal stress. Thus, it
is possible to avoid the occurrence of cracks and defects in the
thermoelectric elements 37 due to thermal stress, and it is
possible to achieve high reliability in the heat exchange device
30.
[0058] Next, an actual manufacturing method of the heat exchange
device 30 will be described below.
[0059] The first corrugated fins 31 composed of copper, a copper
alloy, aluminum, or an aluminum alloy are fabricated in such a way
that the heat-dissipation electrode 33 is attached to the joint
regions 31a via the insulating resin layer whose thickness ranges
from 10 .mu.m to 100 .mu.m. In addition, the second corrugated fins
34 composed of copper, a copper alloy, aluminum, or an aluminum
alloy are fabricated in such a way that the heat-absorption
electrode 36 is attached to the joint regions 34a via the
insulating resin layer whose thickness ranges from 10 .mu.m to 100
.mu.m. Furthermore, the thermoelectric elements 37 are formed using
P-type and N-type semiconductor compounds.
[0060] The heat-dissipation electrode 33 and the heat-absorption
electrode 36 are each composed of a copper film or copper alloy
film, wherein they are each formed in a prescribed electrode
pattern with a prescribed thickness ranging from 70 .mu.m to 200
.mu.m by way of DBC (Direct Bonding Copper). Nickel plating is
adapted to the distal ends (i.e. opposite ends in the longitudinal
direction) of P-type and N-type semiconductor compounds.
[0061] The thermoelectric elements 37 are arranged above the
heat-absorption electrode 36 (composed of a copper film or copper
alloy film) attached to the second corrugated fins 34 such that
P-type and N-type semiconductor compounds are alternately aligned.
The first corrugated fins 31 attached to the heat-dissipation
electrode 33 (composed of a copper film or copper alloy film) are
arranged above the thermoelectric elements 37. The upper ends of
the thermoelectric elements 37 composed of P-type and N-type
semiconductor compounds below the heat-dissipation electrode 33 are
soldered to the lower surfaces of the heat-dissipation electrode 33
via soldering materials such as an SnSb alloy, SnAu alloy, and
SnAgCu alloy, while the lower ends of the thermoelectric elements
37 are soldered to the upper surface of the heat-absorption
electrode 36 via soldering materials such as an SnSb alloy, SnAu
alloy, and SnAgCu alloy.
[0062] The thermoelectric elements 37 are connected in series
between the heat-dissipation electrode 33 and the heat-absorption
electrode 36 via the solder layers 37a such that P-type and N-type
semiconductor compounds thereof are alternately aligned.
Thereafter, the leads 38 are soldered to the terminals 36a on one
end of the heat-absorption electrode 36, thus completing the
production of the heat exchange device 30.
4. FOURTH EMBODIMENT
[0063] FIG. 4 is a cross-sectional view showing the constitution of
a heat exchange device 40 according to a fourth embodiment of the
present invention.
[0064] In the heat exchange devices 10, 20, and 30, a series of
electrodes (e.g. four electrodes in the illustrations of FIGS. 1 to
3) is linearly aligned along the joint regions of the corrugated
fins; however, plural electrodes are not necessarily aligned in a
single line along the joint regions of the corrugated fins but can
be aligned in plural lines. The heat exchange device 40 of the
fourth embodiment is designed such that plural electrodes are
aligned in two lines along the joint regions of the corrugated
fins. As shown in FIG. 4, the heat exchange device 40 has a
thermoelectric module 40a similar to the thermoelectric module 10a
installed in the heat exchange device 10.
[0065] The heat exchange device 40 includes first corrugated fins
41 (which collectively serve as a heat-dissipation side heat
exchanger), heat-dissipation electrodes 43 which are attached to
the lower surfaces of the first corrugated fins 41 via insulating
resin layers 42 having high thermal conductivity and an adhesive
property, second corrugated fins 44 (which collectively serve as a
heat-absorption side heat exchanger), and heat-absorption
electrodes 46 which are attached to the upper surfaces of the
second corrugated fins 44 via insulating resin layers 45 having
high thermal conductivity and an adhesive property. A plurality of
thermoelectric elements 47 are electrically connected in series and
disposed between the electrodes 43 and 46 via solder layers (or
metals) 47a. A pair of terminals 46a is formed on one end of the
heat-absorption electrode 46 so as to establish an electrical
connection with a pair of leads 48.
[0066] Both of the first corrugated fins 41 and the second
corrugated fins 44 are composed of the foregoing material used for
the corrugated fins 13. The first corrugated fins 41 are
constituted of joint regions 41a and non-joint regions 41b which
project upwardly from gaps between adjacent joint regions 41a,
while the second corrugated fins 44 are constituted of joint
regions 44a and non-joint regions 44b which project downwardly from
gaps between adjacent joint regions 44a. Specifically, as shown in
FIGS. 5A and 5B, four electrodes 43 are aligned in two lines
respectively on the joint region 41a of the first corrugated fin
41, while four electrodes 46 are aligned in two lines respectively
on the joint region 44a of the second corrugated fin 44. The width
"X" of the joint region 41a (and 44a ) is expressed as X=2x+y,
which is larger than the width "x" of the joint region 13a in the
heat exchange device 10 (similarly the joint regions 21a and 25a in
the heat exchange device 20, and the joint regions 31a and 34a in
the heat exchange device 30) by "x+y".
[0067] Both the insulating resin layers 42 and 45 are composed of
the foregoing material used for the insulating resin layer 14;
specifically, they are each composed of a polyimide resin or epoxy
resin with a thickness ranging from 10 .mu.m to 100 .mu.m. Fillers
such as powder particles composed of alumina (Al.sub.2O.sub.3),
aluminum nitride (AlN), or magnesium oxide (MgO) and having an
average particle diameter of 15 .mu.m or less are dispersed and
doped in the polyimide resin or epoxy resin so as to improve its
thermal conductivity. Similar to the heat-dissipation electrode 12
and the heat-absorption electrode 15, the heat-dissipation
electrodes 43 and the heat-absorption electrodes 46 are each
composed of a copper film or copper alloy film with a thickness
ranging from 70 .mu.m to 200 .mu.m. A plurality of thermoelectric
elements 47 is electrically connected in series and disposed
between the electrodes 43 and 46.
[0068] The upper ends of the thermoelectric elements 47 are
soldered to the heat-dissipation electrodes 43 via soldering
materials such as an SnSb alloy, SnAu alloy, and SnAgCu alloy,
while the lower ends of the thermoelectric elements 47 are soldered
to the heat-absorption electrodes 46 via soldering materials, thus
forming the solder layers 47a. The composition of the
thermoelectric elements 47 is identical to the composition of the
thermoelectric elements 16.
[0069] Since the heat exchange device 40 does not use a substrate,
it is possible to reduce thermal resistance, thus improving the
maximum heat absorption coefficient (Qmax). None of the insulating
resin layers 42 and the heat-dissipation electrodes 43 is formed in
gaps between adjacent joint regions 41a of the first corrugated
fins 41, wherein these gaps absorb thermal stress. None of the
insulating resin layers 46 and the heat-absorption electrodes 46 is
formed in gaps between the joint regions 44a of the second
corrugated fins 44, wherein these gaps absorb thermal stress. Thus,
it is possible to avoid the occurrence of cracks and defects in the
thermoelectric elements due to thermal stress, and it is possible
to achieve high reliability in the heat exchange device 40.
[0070] Next, an actual manufacturing method of the heat exchange
device 40 will be described below.
[0071] The first corrugated fins 41 composed of aluminum or an
aluminum alloy are fabricated in such a way that the
heat-dissipation electrodes 43 are attached to the joint regions
41a via the insulating resin layers 42 whose thickness ranges from
10 .mu.m to 100 .mu.m. In addition, the second corrugated fins 44
composed of copper, a copper alloy, aluminum, or an aluminum alloy
are fabricated in such a way that the heat-absorption electrodes 46
are attached to the joint regions 44a via the insulating resin
layers 45 whose thickness ranges from 10 .mu.m to 100 .mu.m.
Furthermore, the thermoelectric elements 47 are formed using P-type
and N-type semiconductor compounds.
[0072] Both of the heat-dissipation electrodes 43 and the
heat-absorption electrodes 46 are each composed of a copper film or
copper alloy film and are each formed in a prescribed electrode
pattern with a prescribed thickness ranging from 70 .mu.m to 200
.mu.m by way of DBC (Direct Bonding Copper). As shown in FIG. 5A,
the four heat-dissipation electrodes 43 are aligned in two lines
respectively on the joint region 41a of the first corrugated fin
41, while the four heat-absorption electrodes 46 are aligned in two
lines respectively on the joint region 44a of the second corrugated
fin 44. Nickel plating is applied to the distal ends (i.e. opposite
ends in the longitudinal direction) of P-type and N-type
semiconductor compounds in the thermoelectric elements 47.
[0073] The P-type and N-type semiconductor compounds of the
thermoelectric elements 47 are alternately aligned on the
heat-absorption electrodes 46 (composed of a copper film or copper
alloy film) formed on the second corrugated fins 44. The first
corrugated fins 41 having the heat-dissipation electrodes 43
(composed of a copper film or copper alloy film) are disposed above
the thermoelectric elements 47. The upper ends of the
thermoelectric elements 47 are soldered to the heat-dissipation
electrodes 43 via soldering materials such as an SnSb alloy, SnAu
alloy, and SnAgCu alloy, while the lower ends of the thermoelectric
elements 47 are soldered to the heat-absorption electrodes 46 via
soldering materials.
[0074] Thus, the P-type and N-type semiconductor compounds of the
thermoelectric elements 47 are alternately aligned and connected in
series between the heat-dissipation electrodes 43 and the
heat-absorption electrodes 46 via the solder layers 47a.
Thereafter, the leads 48 are soldered to the terminals 46a on one
end of the heat-absorption electrode 46, thus completing the
production of the heat exchange device 40.
[0075] The heat exchange device 40 is designed such that plural
electrodes are aligned in two lines on the joint region of the
corrugated fin; but this is not a restriction. It is possible to
align plural electrodes in plural lines on the joint region of the
corrugated fin. FIGS. 6A and 6B show a variation of the fourth
embodiment, i.e. a heat exchange device 40A in which the four
heat-dissipation electrodes 43 are aligned in four lines
respectively on the joint region 41a of the first corrugated fin 41
and in which the four heat-absorption electrodes 46 are aligned in
four lines on the joint region 44a of the second corrugated fin 44.
In the heat exchange device 40A, both of the first corrugated fins
41 and the second corrugated fins 44 are composed of the foregoing
material used for the corrugated fins 13; the first corrugated fins
41 are constituted of the joint regions 41a and the non-joint
regions 41b (which project upwardly from gaps between adjacent
joint regions 41a); and the second corrugated fins 44 are
constituted of the joint regions 44a and the non-joint regions 44b
(which project downwardly from gaps between adjacent joint regions
44a). In addition, the width "X" of the joint regions 41a and 44a
is expressed as X=4x+3y, which is larger than the width "x" of the
joint region 13a in the heat exchange device 10 (similar to the
joint regions 21a and 25a in the heat exchange device 20, and the
joint regions 31a and 34a in the heat exchange device 30) by
"3x+3y".
5. EVALUATION TESTING
[0076] (1) Performance Evaluation (i.e. Maximum heat Absorption
Coefficient Qmax)
[0077] Maximum heat absorption coefficients (Qmax) which indicate
indexes of performance evaluation were measured with respect to the
heat exchange devices 10, 20, 30, 40, and 40A as well as the
conventionally-known heat exchange device 50 shown in FIG. 7.
[0078] Test examples A1-A2, B1-B3, C1-C6, D1-D2, E1-E2, and X were
respectively produced in accordance with the heat exchange devices
10, 20, 30, 40, 40A, and 50. The test examples A1-A2, B1-B3, C1-C6,
D1-D2, E1-E2, and X were each placed in a bell jar, in which they
were each held by a soaking copper plate having high thermal
capacity, silicon grease was applied to the joining area between
the corrugated fins and the soaking copper plate, then, measurement
was performed in a vacuum atmosphere. Measurement results are shown
in Table 1.
TABLE-US-00001 TABLE 1 Test Insulating Resin Layer Corrugated Fins
Qmax Example Substrate Material Filler Position Alignment (W) A1
One side Polyimide Alumina One side One line 221 (One side)
(Substrate) A2 One side Epoxy Alumina One side One line 222 (One
side) (Substrate) B1 None Polyimide Alumina Both sides One line 221
(Copper) B2 None Epoxy Alumina Both sides One line 220 (Copper) B3
None Epoxy Alumina: 50% Both sides One line 223 (Copper) AlN: 50%
C1 None Epoxy Alumina Both sides One line 225 C2 None Epoxy AlN
Both sides One line 223 C3 None Epoxy MgO Both sides One line 222
C4 None Polyimide Alumina Both sides One line 222 C5 None Polyimide
AlN Both sides One line 220 C6 None Polyimide MgO Both sides One
line 224 D1 None Epoxy Alumina: 50% Both sides Two lines 224 AlN:
50% D2 None Polyimide Alumina: 50% Both sides Two lines 225 MgN:
50% E1 None Polyimide Alumina: 50% Both sides Four lines 224 MgO:
50% E2 None Epoxy Alumina: 50% Both sides Four lines 225 MgO: 50% X
Both Epoxy Alumina One side One line 208 sides (Substrate)
[0079] In the measurement, the composition of P-type semiconductor
compounds is expressed as Bi.sub.0.4Sb.sub.1.6Te.sub.3, while the
composition of N-type semiconductor compounds is expressed as
Bi.sub.1.9Sb.sub.0.1Te.sub.2.7Se.sub.0.3. The above semiconductor
compounds are subjected to rapid cooling so as to produce foil
powder, which is then subjected to hot pressing so as to bulk into
a semiconductor material, which is cut into individual pieces each
having dimensions of 1.5 mm (length).times.1.5 mm (width).times.1.0
mm (height). One hundred pairs of pieces are used for the
measurement, wherein the electrodes 12, 15, 24, 27, 33, and 36 are
all formed in a prescribed thickness of 120 .mu.m, and each
electrode has dimensions of 1.8 mm.times.3 mm. The corrugated fins
13, 21, 25, 31, 34, 41 and 44 composed of copper are each formed in
dimensions of 40 mm (length).times.40 mm (width).times.10 mm
(height).
[0080] The test examples A1 and A2 are produced based on the heat
exchange device 10 of the first embodiment, in which the substrate
11 and the insulating resin layer 14 are each composed of a
polyimide resin and epoxy resin doped with fillers composed of
aluminum powder and are each formed with a thickness of 10 .mu.m;
specifically, the heat exchange device A1 is produced using the
polyimide resin, while the heat exchange device A2 is produced
using the epoxy resin.
[0081] The text examples B1, B2, and B3 are produced based on the
heat exchange device 20 of the second embodiment, in which the
insulating resin layers 24 and 26 are each composed of a polyimide
resin and epoxy resin doped with fillers composed of alumina powder
and a mixed powder consisting of 50% alumina power and 50% aluminum
nitride (AlN) powder (in volume percentage) and are each formed
with a thickness of 20 .mu.m; specifically, the heat exchange
device B1 is produced using the polyimide resin doped with alumina
fillers, the heat exchange device B2 is produced using the epoxy
resin doped with alumina fillers, and the heat exchange device B3
is produced using the epoxy resin doped with fillers composed of
alumina powder (50%) and aluminum nitride powder (50%).
[0082] Test examples C1 to C6 are produced based on the heat
exchange device 30 of the third embodiment, in which the insulating
resin layers 32 and 35 are each composed of an epoxy resin and
polyimide resin doped with fillers composed of alumina powder,
aluminum nitride (AlN) powder, and magnesium oxide (MgO) powder and
are each formed with a thickness of 20 .mu.m; specifically, the
heat exchange device C1 is produced using the epoxy resin doped
with alumina fillers; the heat exchange device C2 is produced using
the epoxy resin doped with aluminum nitride fillers; the heat
exchange device C3 is produced using the epoxy resin doped with
magnesium oxide fillers; the heat exchange device C4 is produced
using the polyimide resin doped with alumina fillers; the heat
exchange device C5 is produced using the polyimide resin doped with
aluminum nitride fillers; and the heat exchange device C6 is
produced using the polyimide resin doped with magnesium oxide
fillers.
[0083] The test examples D1 and D2 are produced based on the heat
exchange device 40 of the fourth embodiment, in which the
insulating rein layers 42 and 45 are each composed of an epoxy
resin and polyimide resin doped with fillers composed of 50%
alumina powder together with 50% aluminum nitride (AlN) powder or
50% magnesium oxide (MgO) powder (in volume percentage) and are
each formed with a thickness of 20 .mu.m; specifically, the heat
exchange device D1 is produced using the epoxy resin doped with
alumina fillers (50%) and aluminum nitride fillers (50%), and the
heat exchange device D2 is produced using the polyimide resin doped
with alumina fillers (50%) and magnesium oxide fillers (50%).
[0084] The text examples E1 and E2 are produced based on the heat
exchange device 40A according to a variation of the fourth
embodiment, in which the insulating resin layers 42 and 45 are each
composed of a polyimide resin or epoxy resin doped with fillers
composed of 50% alumina powder and 50% magnesium oxide (MgO) powder
(in volume percentage); specifically, the heat exchange device E1
is produced using the polyimide resin doped with alumina fillers
(50%) and magnesium oxide fillers (50%), and the heat exchange
device E2 is produced using the epoxy resin doped with alumina
fillers (50%) and magnesium oxide fillers (50%).
[0085] The test example X is produced based on the
conventionally-known heat exchange device 50 shown in FIG. 7, in
which the support structures 51 and 56 are each composed of an
epoxy resin doped with fillers composed of alumina powder and are
each formed with a thickness of 20 .mu.m, thus fabricating the heat
exchange device X.
[0086] Table 1 clearly shows that all the heat exchange devices
A1-A2, B1-B3, C1-C6, D1-D2, and E1-E2 based on the heat exchange
devices 10, 20, 30, 40, and 40A are improved in the maximum heat
absorption coefficient (Qmax) in comparison with the heat exchange
device X corresponding to the conventionally-known heat exchange
device 50. This is because the heat exchange devices according to
the present invention are designed without using a substrate or
only using a substrate on one side, thus reducing thermal
resistance.
[0087] (2) Reliability Evaluation (i.e. Variations of
Alternating-Current Resistance ACR)
[0088] By use of the heat exchange devices A1-A2, B1-B3, C1-C6,
D1-D2, E1-E2, and X, variations (i.e. increase ratios) of
alternating-current resistance (ACR) which indicates a significant
index of reliability evaluation were measured in the following
condition. The heat exchange devices A1-A2, B1-B3, C1-C6, D1-D2,
E1-E2, and X were initially placed in a prescribed environmental
condition of 95% humidity and 30.degree. C. temperature and were
then heated for two minutes such that the temperature difference
between the upper portion and lower portion thereof increased from
10.degree. C. to 90.degree. C. and was then sustained for one
minute; thereafter, they were cooled for three minutes such that
the temperature difference decreased from 90.degree. C. to
10.degree. C. Such a temperature increase/decrease cycle (or a
thermal cycle) was repeated for 10,000 times to 100,000 times.
[0089] At 10,000 cycles, 20,000 cycles, 40,000 cycles, 60,000
cycles, 80,000 cycles, and 100,000 cycles, alternating-current
resistances (ACR) were measured with respect to the heat exchange
devices A1-A2, B1-B3, C1-C6, D1-D2, E1-E2, and X, thus estimating
ACR variations compared to ACR before the temperature
increase/decrease cycle. In addition, at 10,000 cycles, 20,000
cycles, 40,000 cycles, 60,000 cycles, 80,000 cycles, and 100,000
cycles, maximum heat absorption coefficients (Qmax) were measured
with respect to the heat exchange devices A1-A2, B1-B3, C1-C6,
D1-D2, E1-E2, and X, thus estimating variations compared to Qmax
before the temperature increase/decrease cycle. The results
regarding variations of ACR and Qmax are shown in Table 2.
TABLE-US-00002 TABLE 2 ACR variations (%) and Qmax variations (%)
after thermal cycle Test 10,000 20,000 40,000 60,000 80,000 100,000
Ex. ACR Qmax ACR Qmax ACR Qmax ACR Qmax ACR Qmax ACR Qmax A1 0 0 0
0 0 0 1.1 0 1.2 0.5 1.8 0.5 A2 0 0 0 0 0 0 1.1 0 1.1 0.3 1.9 0.5 B1
0 0 0 0 0 0 1.1 0 1.2 0.4 1.8 0.5 B2 0 0 0 0 0 0 1.1 0 1.2 0.3 1.6
0.6 B3 0 0 0 0 0 0 0 0 0.8 0.2 1.1 0.4 C1 0 0 0 0 0 0 0 0 0.8 0 1.1
0.2 C2 0 0 0 0 0 0 0 0 0.7 0 1.1 0.2 C3 0 0 0 0 0 0 0 0 0.8 0 1.1
0.2 C4 0 0 0 0 0 0 0.2 0 0.7 0 1.2 0.2 C5 0 0 0 0 0 0 0.3 0 0.8 0.2
1.1 0.3 C6 0 0 0 0 0 0 1.1 1.1 1.5 1.2 1.8 1.8 D1 0 0 0 0 0 0 1.1
1.1 1.5 1.5 2.0 2.0 D2 0 0 0 0 0 0 1.1 1.1 1.3 1.3 1.6 1.5 E1 0 0 0
0 0 0 1.1 1.1 1.5 1.5 1.7 1.7 E2 0 0 0 0 0 0 1.2 1.2 1.4 1.4 1.3
1.6 X 0 0 0 0 0 0 3.2 5.2 7.1 8.9 12.3 20.2
[0090] Table 2 clearly shows that, when the number of thermal
cycles exceeds 60,000 cycles, both the ACR variations (%) and Qmax
variations (%) are controlled with respect to the heat exchange
devices A1-A2, B1-B3, C1-C6, D1-D2, and E1-E2 based on the heat
exchange devices 10, 20, 30, 40, and 40A compared to the heat
exchange device X corresponding to the conventionally-known heat
exchange device 50. This is because the heat exchange devices of
the present invention are designed without using a substrate or
only using a substrate on one side while gaps are formed between
the electrodes 15, the electrodes 27, the electrodes 33, the
electrodes 36, the electrodes 43, and the electrodes 46, thus
absorbing thermal stress.
6. INDUSTRIAL APPLICABILITY
[0091] All the embodiments of the present invention are designed to
use polyimide resins and epoxy resins as composite resin materials;
but this is not a restriction. It is possible to use other resins
such as aramid resins and bismaleimide triazine (BT) resins other
than polyimide resins and epoxy resins, thus achieving the
aforementioned properties.
[0092] All the embodiments of the present invention are designed to
use alumina powder, aluminum nitride powder, and magnesium oxide
powder as filler materials; but this is not a restriction. It is
possible to use other materials of high heat conductivity such as
carbon powder, silicon carbide, and silicon nitride. One kind of
filler material is satisfactory, but it is possible to mix two or
more kinds of filler materials. In addition, fillers can be formed
in arbitrary shapes such as spherical shapes and needle shapes as
well as mixtures of such shapes.
[0093] Last, the present invention is not necessarily limited to
the above embodiments and variations, which can be further modified
within the scope of the invention as defined in the appended
claims.
* * * * *