Patent Application
20120298163
1. Field of the Invention
The present invention relates to a thermoelectric unit
2. Description of the Background Art
The energy stored in exhaust gas in the form of heat has hitherto been discharged into the environment unused. In order to increase the effectiveness of a system, e.g., a vehicle, and consequently to reduce the discharge of CO2 in operation, a thermoelectric generator (TEG) can be implemented, the thermoelectric module (TEM) of which converts part of the heat into electric energy and feeds it back into the system. The TEG can be accommodated with different use at any point in the exhaust gas system or in the exhaust gas recirculation. Current-operated, the TEG can also be used as a thermoelectric heater or cooler (TE-HC).
EP 1 475 532 A2, which corresponds to U.S. Pat. No. 7,100,369 discloses a thermoelectric generator with a thermoelectric element, which uses the exhaust gas from an engine as a high-temperature heat source and an engine coolant as a low-temperature heat source to generate electricity. A valve regulates the supply of the exhaust gas to the thermoelectric element according to the load of the engine.
Conventional TEMs according to the prior art are not optimally suitable for use in a TEG due to their design and joining technique and also are less effective. Furthermore, the TEMs must be electrically connected and integrated in an optimal manner.
Conventional TEGs are less efficient due to the increased heat transmission resistance between thermoelectrically active materials and a heat source/heat sink. An integration of the TEM into a heat exchanger has also proven to be impractical. Joining techniques hitherto available are sometimes not high-temperature stable. Furthermore, on the gas-side contact of the TEM in the heat exchanger there is often only a low heat transfer. According to the prior art, accordingly conventional TEMs are not optimally suitable for use in a TEG due to their design and joining technique and are less effective. The electrical connection is often complex and unstable.
It is therefore an object of the present invention to provide an improved thermoelectric unit.
The present invention is based on the realization that a larger quantity of thermoelectric modules can be very easily connected to one another by a favorable design of the electrical connection contacts. In this manner the advantages of the thermoelectric elements can be efficiently utilized even with compact heat exchangers.
The present invention creates a thermoelectric unit for the electrical connection of a plurality of thermoelectric modules, wherein the thermoelectric unit has the following features: a first thermoelectric module, which has a plurality of thermoelectric elements interconnected to one another, wherein the first thermoelectric module is arranged between a main surface of an inner flat tube and a main surface of an outer flat tube of a double-walled cooling tube; a second thermoelectric module, which has a plurality of thermoelectric elements interconnected to one another, wherein the second thermoelectric module is arranged between a further main surface of the inner flat tube and a further main surface of the outer flat tube of the double-walled cooling tube and/or between a main surface of an inner flat tube and a main surface of an outer flat tube of a further double-walled cooling tube; and an electrical connector, which is embodied to connect the first thermoelectric module to the second thermoelectric module in an electrically conducting manner.
The thermoelectric modules (or TEM for short) can be used, e.g., in a heat exchanger. The heat exchanger can be used in a vehicle either as a thermoelectric generator or as a thermoelectric heater and cooler. For example, with a use of the heat exchanger as a thermoelectric generator or TEG, two differently temperature-controlled and spatially separated media or fluids are guided past one another such that an electric current is generated in the thermoelectric modules. The thermoelectric elements can be, for example, differently doped semiconductor materials. The thermoelectric elements can be arranged as a plurality of blocks between the main surfaces of the inner and outer flat tube and have electric conductors via which the individual blocks are connected to one another in an electrically conducting manner. A double-walled cooling tube thus in general has two thermoelectric modules or TEMs arranged one above the other viewed in cross section. The double-walled cooling tube can thus also be referred to as a TEM tube. The double-walled cooling tube can have, e.g., a rectangular cross section, thus can be composed of an inner rectangular tube and an outer rectangular tube surrounding it. The main surfaces of the inner flat tube and of the outer flat tube are thus the larger areas of the inner and outer rectangular tube lying opposite one another. For example, one of the two differently temperature-controlled fluids of the heat exchanger is guided inside the inner tube of the TEM tube. This can be, e.g., a coolant from the engine cooling circuit of the vehicle. The other of the two differently temperature-controlled fluids can be, e.g., exhaust gas from an internal combustion engine of the vehicle and be guided on an outside of the outer tube of the double-walled cooling tube. As a result of the temperature difference of the two media, current can be generated in the thermoelectric modules arranged between the inner tube and the outer tube. In general a heat exchanger has a plurality of double-walled cooling tubes arranged e.g., in a layered manner with respectively one thermoelectric module in each intermediate space between the main surfaces of the inner and outer flat tubes. The electrical connectors can be differently shaped and electrically conducting metal elements. These can be embodied in order to connect the two thermoelectric modules inside a double-walled cooling tube and at the same time or alternatively to connect them to the thermoelectric modules of a further double-walled cooling tube in an electrically conducting manner.
According to an embodiment, the inner flat tube of the double-walled cooling tube can have a greater length than the outer flat tube of the double-walled cooling tube and the inner flat tube of the further double-walled cooling tube can have a greater length than the outer flat tube of the further double-walled cooling tube, such that at least on one side the ends of the inner flat tubes project beyond the corresponding ends of the outer flat tubes, wherein the electrical connector extends from the projecting end of the inner tube of the double-walled cooling tube to the projecting end of the inner tube of the further double-walled cooling tube. Advantageously, conductor connections for the electrically conducting connection of thermoelectric modules of a plurality of cooling tubes can be positioned and fixed in a simple manner.
For example, the electrical connector can be embodied as a one-part clamp, which laterally spans the inner flat tube on a lateral surface of the double-walled cooling tube, wherein a first end of the connector contacts the first thermoelectric module of the double walled cooling tube and a second end or an intermediate contact of the connector contacts the further thermoelectric module of the double-walled cooling tube. An electrical connector of this type can be produced simply and cost-effectively and is easy to use. The contacting can be carried out, e.g., via an insertion of the end and of the second end or of the intermediate contact between one of the elements of the thermoelectric module and the inner flat tube. The one-piece clamp can bear entirely against the inner flat tube or can be spaced apart from a lateral surface of the inner flat tube.
According to a further embodiment, the electrical connector can be embodied as a one-part multiple connector clamp, which laterally spans the inner flat tube of the double-walled cooling tube and the inner flat tube of the at least one further double-walled cooling tube on one lateral surface, wherein the multiple connector clamp is embodied in order to connect two thermoelectric modules assigned to the double-walled cooling tube to at least one thermoelectric module of a further double-walled cooling tube. In this embodiment the electrical connector can also be produced simply and cost-effectively and is easy to place and to attach, in particular when it is necessary to connect the thermoelectric modules of several cooling tubes.
The electrical connector can also be embodied as a multipart clamp, of which a first part spans a lateral surface of the inner flat tube of the double-walled cooling tube and at least one second part spans the inner flat tube of a further double-walled cooling tube on a lateral surface, wherein the first part and the second part can be connected positively in order to connect in an electrically conducting manner at least one thermoelectric module assigned to the double-walled cooling tube to at least one thermoelectric element assigned to the further double-walled cooling tube. For example, the one part and the at least one further part can be embodied as hooks that can engage in one another. This embodiment provides the advantage that, due to the separate steps of the positioning and connecting of the at least two parts of the clamp, an attachment and removal of the electric connector can be facilitated.
According to a further embodiment, the electrical connector can be spanned by a narrow side of the inner tube and have a bushing in the region of a subsidiary surface of the inner tube connecting the main surfaces of the inner tube, which bushing can be embodied to be connected to an insert conductor in an electrically conducting manner. The insert conductor can be, e.g., an electrically insulated copper cable or a conductor clamp, with which individual TEM tubes can be connected or a connection can be produced to an external power supply. This makes it possible to quickly contact the individual thermoelectric modules even over several cooling tubes.
The outer flat tube of the double-walled cooling tube can also have a first opening and, on a main surface of the outer flat tube of the further double-walled cooling tube, have a second opening, which is arranged at a position lying opposite the first opening and wherein the electrical connector is embodied as a pin plug, which is guided through the first opening and the second opening. By means of such openings in connection with pin plugs, there is a particularly space-saving possibility of connecting thermoelectric modules in an electrically conducting manner.
According to an embodiment, the pin plug can have a non-conducting sheath. The plug connector can be embodied as a double plug or a conductor pin with an electrically conducting core and an electrically insulated sheath, so that an improved electrical insulation of the contact between the thermoelectric modules and an environment is ensured. Particularly with adverse environmental conditions of the thermoelectric unit, such as in vehicle use, this will lead to an increased service life of the same.
According to a further embodiment, the electrical connector can have a first part, which can be embodied as a prong connected to the thermoelectric module in an electrically conducting manner, which prong projects out of an opening of a main surface of the outer flat tube of the double-walled cooling tube and wherein the electrical connector furthermore can have a second part which likewise can be embodied as an electrically conducting prong, wherein the second part is connected to a second thermoelectric module in a conducting manner, which is assigned to a further double-walled cooling tube, and wherein the second part projects out of an opening of a main surface of the outer flat tube of the second double-walled cooling tube. The first and the second part of the electrical connector can be in electrically conducting contact with one another. For the electrical connection of the thermoelectric module to a further thermoelectric module, the double-walled cooling tube can thereby be arranged closely adjacent to a further double-walled cooling tube such that the prongs connected to the respective thermoelectric module can contact one another. Here too an electric insulation of the prong with respect to the surrounding medium can be provided, whereby the advantages referenced above in turn can be achieved.
The electrical connector can also be embodied as a cable, the end of which can be connected through an opening of a main surface of the outer flat tube of the double-walled cooling tube to the thermoelectric module in an adhesive and electrically conducting manner. With this embodiment, the required material expenditure can be kept particularly low, wherein a secure electrical contacting of the individual thermoelectric modules is also guaranteed by the adhesive connection. In contrast, a production expenditure for a connection of this type will be higher than a production and attachment expenditure for the connection to a correspondingly shaped clamp.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:
In the following description of favorable exemplary embodiments of the present invention the same or similar reference characters are used for the elements shown in the various drawings with similar action, a repeated description of these elements being omitted.
A TEM tube according to the exemplary embodiments of the invention presented here is formed by a two-walled rectangular tube, wherein TE-active materials are introduced into an intermediate space of the two walls. An inner tube of the TEM tube is in contact with one of two fluids flowing through a TEG, an outer tube of the TEM tube is in contact with the other of the two fluids flowing through the TEG.
Various exemplary embodiments for inner and/or outer tubes of the two-walled rectangular tube are shown in
Thus
The inner 7 as well as the outer tube 8 is produced essentially from a metallic material, preferably of a stainless steel, e.g., 1.4404. However, an aluminum or copper material for lower use temperatures is also conceivable.
The two tubes 7, 8 are covered in part or entirely with an electrically non-conducting material 15 at least on their sides facing towards an intermediate space between the tubes 7, 8, so that TE material and tubes 7, 8 or electrical conductor and tubes 7, 8 are electrically insulated with respect to one another. This non-conducting material 15 can be, for example, a ceramic coating or a ceramic sheet 15. The non-conducting material 15 can be applied, for example, via a soldering or sintering process, wherein to this end the tubes 7, 8 can be pretreated in a different manner. For example, the tubes 7, 8 can be electroplated or printed, or they can also be equipped with an additional coating, e.g., of tungsten or silver.
The outer tube 8 and/or the inner tube 7 can have the profile 20 on a respective side assigned to a fluid. In the exemplary embodiments shown in
The outer tube 8 and/or the inner tube 7 can respectively be structured in a one-part or multipart manner. In the case of a two-part structure, the tube is then assembled from an upper part 18 and a lower part 19 in the form of e.g. two half-shells. The upper part 18 and the lower part 19 have the joint seam 21 in a lateral region of the tube, that is, on a short tube wall side.
Accordingly,
Thus
The tubes 7, 8 can have the seams 21, regardless of whether they are produced in a one-part or multipart manner.
The tubes 7, 8 can have openings 22 for an electrical connection of the TEM.
Accordingly,
The TE materials 5 are located in the upper as well as in the lower flat gap of the intermediate space 11, that is, on the long tube wall side of the TEM tube 4, but not in the lateral region 12, which is located on the short tube wall side. In this respect the TEM tube 4 is composed essentially of two planar TEMs or TEM modules 2, which are located parallel opposite one another, and create the interior 13 located between them, which receives the first 9 of the two fluids 9, 10 and is delimited laterally to the outside. The intermediate space of the lateral region 12 can represent a thermal separation between interior 13 and exterior 14. The intermediate space 6 in addition can be filled with an inert gas or with a non-conducting material, in order to protect the TE materials 5. The non-conducting material can be formed, for example, by a plastic, an adhesive, e.g. on silicone basis or a ceramic.
The conductors 16 are connected to the TE materials 5, e.g., by soldering and thus interconnect them electrically parallel or in series to one another. A barrier layer 17 can be inserted between a conductor 16 and an actual TE material 5, which barrier layer protects the TE materials 5 or a doping of the TE materials 5 in use.
The axial ends of the TEM tubes 4 can be closed with respect to the intermediate space 6, so that neither the first fluid 9 nor the second fluid 10 can penetrate into the intermediate space 6 and the TEM 2 is encapsulated. This can be carried out via a TEM tube cover 23, which axially closes the intermediate space 6.
Accordingly,
The inner contour 24 of the TEM tube cover 23 is thereby connected to the inner tube 7, and the outer contour 25 of the TEM tube cover 23 is connected to the outer tube 8. The cover 23 thus ensures an unimpeded flow through of the interior 13 and of the exterior 14 of the TEM tube 4. The cover 23 can be flush with the tube 3 or can be set back with respect to the inner tube 7, when the outer tube 8 is shorter than the inner tube 7. The TEM tube cover 23 can be insulated with respect to the electrical components 16, 5 of the TEM tube 4.
In terms of production engineering, firstly the inner tube 7 can be equipped with the TEM 2 on both sides and subsequently the outer tube 8 can be added. Joined outer tube 8, TEM 2, inner tube 7 and optionally also the TEM tube cover 23 can subsequently be subjected to a heat treatment, e.g., a furnace brazing, so that the components are connected to one another.
The TEG is composed essentially of a plurality of TEM tubes 4 stacked one of top of the other, as well as bases 30, diffusers 26, a housing 27 and various electrical components such as e.g. lines and/or plug connectors, which connect the TEG outwardly electronically as well as also optionally the TEM tubes 4 in series or parallel to one another. For the electrical connection of the TEG, the diffusers 26 and/or the housing 27 are embodied with openings in this respect. For the sake of clarity, the TEG shown isometrically in
It can be seen from
The first fluid can be supplied to the TEG shown by way of example in
The bases 30 separate a region of the first fluid in the TEG from a region of the second fluid.
It is not shown in
The inner tube of the TEM tube can be flush with the outer tube. The outer tube can also be set back with respect to the inner tube. Corresponding exemplary embodiments are illustrated in
Thus the sectional image of the exemplary embodiment in
Depending on how the outer tube and inner tube are designed, and whether a TEM tube cover is used, and also how the electrical connection of the TEM tubes is accomplished, an inner tube base and/or an outer tube base is used
Accordingly,
The various possibilities of an electrical connection of individual thermoelectric modules are explained below.
In general, the TE-active materials or thermoelectric modules can be interconnected to one another in series and/or in a parallel manner in the lower and upper gap of the intermediate space in a TEM tube. The TE-active materials of the lower gap of the intermediate space can be connected to the TE-active materials of the upper gap of the intermediate space in series or in a parallel manner. The TEM tubes can be connected to one another in series and/or in a parallel manner. The electrically conducting connections outside the TEM tubes, which are in contact with the first fluid and/or the second fluid, if applicable must be electrically insulated. The electrical connection can be carried out in the region of the first fluid, of the second fluid or in the neutral region of the base intermediate space between an outer tube base and an inner tube base. The electrical connection can be non-positive, positive or by adhesive force.
The TE materials of the upper and lower region of the intermediate space can be electrically connected to one another via the conductors thereof and a conductor connector. Optionally, this can also be realized via insert conductors or insert bushings. The conductor connectors are preferably a thin-walled copper sheet.
Different embodiments of the electrical connection, which can be combined with one another, are explained in greater detail below.
The following
Thus
This can be seen more clearly based on the sectional image shown in
In contrast thereto, the partial sectional image in
The conductor connector can furthermore have a bushing as is illustrated based on the isometric image of an exemplary embodiment of a conductor connector 36 in
The isometric image in
Accordingly,
For clarification, the image in
A step for the use of the TEM tube-TEM tube conductor connection 39 is shown based on the isometric image in
Thus
The one-part or multipart conductor connectors 40, 41, 42 shown by way of example in
A further option for the electrically conducting connection of TEM tubes is a TEM tube plug connector.
The TEM tube plug connector 43 interconnects two TEM tubes 4 electrically to one another. For this purpose, the two ends of the TEM tube plug connector 43 are inserted into the openings 22 of the two TEM tubes 4. The TEM tube plug connector 43 has the interior conducting core 46 and the non-conducting sheath 45. The conducting core 46 makes contact with conducting components, e.g., conductors or conductor connections, of the TEM of the TEM tubes 4. The non-conducting sheath 45 electrically insulates in the external region and in the inlet point 22 of the TEM tube plug connector 43 into the tube. The opening 22 thereby becomes fluid-tight. In addition, a sealing adhesive, e.g., silicone, can be applied.
In
Furthermore, TEM tubes 4 can be interconnected by means of a conductor jointing sleeve, as is shown in
According to the exemplary embodiments shown in
According to the exemplary embodiment shown in
The profiling 55 produced by shaping, e.g., embossing, in the tube 7, 8 can make the connection of the TEM, and in particular the TE-active materials and the electric connecting conductor thereof, more difficult in the TEM tube. The intermediate space-side surface of the tube 7, 8 and in particular the shaped profiling 55 thereof, can in this case be provided with a filler material.
A corresponding exemplary embodiment of a filler material 56 for filling the shaped tube profiling 55 is shown in
Alternatively and/or additionally, the intermediate space-side surface of the tube 7, 8 can be covered by a flat metal sheet 59, as is shown in section in
A design and a structure of the thermoelectric module, an incorporation of the thermoelectric module into a thermoelectric generator and an electrical connection of the thermoelectric modules and the generator have thus been explained in connection with the previously described figures.
The exemplary embodiments described are selected merely by way of example and can be combined with one another.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2009 058 674.1 | Dec 2009 | DE | national |
This nonprovisional application is a continuation of International Application No. PCT/EP2010/069784, which was filed on Dec. 15, 2010, and which claims priority to German Patent Application No. DE 10 2009 058 674.1, which was filed in Germany on Dec. 16, 2009, and which are both herein incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2010/069784 | Dec 2010 | US |
| Child | 13525662 | US |
