WO2009100809A2

WO2009100809A2 - Thermo-electric converter and associated production method

Info

Publication number: WO2009100809A2
Application number: PCT/EP2009/000436
Authority: WO
Inventors: Ullrich Hetzler
Original assignee: Isabellenhütte Heusler Gmbh & Co. Kg
Priority date: 2008-02-15
Filing date: 2009-01-23
Publication date: 2009-08-20
Also published as: WO2009100809A3; DE102008009428A1

Abstract

The invention relates to a thermo-electric converter (12), particularly a thermo-electric generator having a support substrate (1) and at least one thermal column having many thermo-elements electrically connected in series and mounted on the support substrate (1). The invention proposes that the support substrate (1) comprises a three-dimensional surface structure having bumps and recesses as structural elements (2).

Description

DESCRIPTION

Theπαo-electrical converter and associated manufacturing method

The invention relates to a thermoelectric converter, in particular a thermoelectric generator, and an associated manufacturing method according to the independent claims.

Thermoelectric generators in the form of so-called thermal columns are known, for example, from DE 10 2007 009 221 A1, DE 20 2006 003 595 U1 and DE 10 2006 007 801 A1 and can be used, inter alia, for level measurement in a fuel tank or for temperature measurement.

In the level sensor according to DE 10 2006 007 801 A1, the individual thermocouples are applied to a flat carrier material, which may be a plastic film.

By contrast, in the case of the thermopile according to DE 20 2006 003 595 U1, an elongate strand (for example a wire) serves as a carrier element for the individual thermocouples.

However, the conventional thermopiles described above are not suitable for microstructuring, so that the production of these known thermopiles is relatively expensive.

The invention is therefore based on the object to reduce the cost of manufacturing in thermopile. This object is achieved by a thermoelectric converter according to the invention and a corresponding manufacturing method according to the independent claims.

The invention comprises the general technical teaching that the carrier substrate for the individual thermocouples has a three-dimensional surface structure with elevations and depressions as structural elements.

In a preferred embodiment of the invention, the individual thermocouples have hot contact points and cold contact points, wherein the hot contact points and the cold contact points are arranged alternately on the elevations and in the depressions of the three-dimensional surface structure of the carrier substrate.

In one variant of the invention, the hot contact points are thus each on the elevations of the three-dimensional surface structure, while the cold contact points are located in the depressions of the three-dimensional surface structure.

Alternatively, however, there is also the possibility that the hot contact points of the thermocouples are each in the depressions of the three-dimensional surface structure, while the cold contact points of the individual thermocouples are each arranged on the elevations of the three-dimensional surface structure of the carrier substrate.

Preferably, the elevations and depressions of the three-dimensional surface structure of the carrier substrate are elongated and thus preferably form protruding ribs or depressions. The individual thermocouples preferably extend with their electrical current direction each transverse to the elongated structural elements of the carrier substrate. This orientation of the thermocouples relative to the structural elements of the three-dimensional surface structure is advantageous because in this way a plurality of thermopiles can be formed by dividing the carrier substrate with the applied thermocouples in the longitudinal direction of the thermopile and transversely to the elongate structural elements, as described in more detail becomes.

In the preferred embodiment with elongated structural elements described above, the individual structural elements preferably each have two lateral flanks, wherein the two conductor layers of the individual thermocouples are respectively applied to the immediately adjacent lateral flanks. In one embodiment of the elongated structural elements as ribs with two side edges, each of the two side edges of the rib can each receive a leg of the same thermocouple in the form of a conductor layer.

In this embodiment with rib-shaped structural elements, the conductor material is preferably applied obliquely, for example by vapor deposition or sputtering. The oblique application of the conductor layers offers the advantage that the rib-shaped structural elements in each case shade one of its two side edges, so that the conductor material is applied in each case only to a single side edge. To coat the opposite side edges, the conductor material must then be applied at a corresponding oblique angle from the other side. The conductor material is therefore preferably not applied exactly at right angles to the surface of the carrier substrate, but with a certain angle of incidence to the surface of the carrier substrate. The angle of incidence of the conductor material may for example be greater than 40 °, 50 °, 60 °, 70 ° or even greater than 80 °, based on the surface of the carrier substrate. Furthermore, the angle of incidence of the conductor material - with respect to the surface of the carrier substrate - can be less than 85 °, 80 °, 70 °, 60 ° or even less than 50 °. Thus, the angle of incidence is preferably in a range of 40 ° to 85 °.

Alternatively, however, within the scope of the invention it is possible to selectively apply the conductor material by means of masks to the side flanks of the rib-shaped structural elements or to remove them again after a coating over the entire surface, e.g. Etching or with lasers.

It should also be noted that the elongate structural elements (e.g., ridges, troughs) of the three-dimensional surface structure of the carrier substrate are preferably aligned substantially parallel to one another and / or substantially perpendicular to the individual thermocouples or thermopiles.

Furthermore, it is advantageous if the structural elements of the three-dimensional surface structure of the carrier substrate are at least partially hollow, since in this way the thermal conductivity of the structural elements is reduced.

Alternatively, however, there is the possibility that the individual structural elements (e.g., ribs) are solid without cavities.

Furthermore, there is the possibility within the scope of the invention that the carrier substrate itself is flat and forms the structural elements (eg ribs, depressions) by its shape, so that the carrier substrate is, for example, corrugated sheet-shaped can be. The carrier substrate may therefore have structural elements on the front side and on the rear side, wherein the structural elements on the front side are formed inversely or complementarily to the structural elements on the rear side. This means, for example, that a rib on the front side of the carrier substrate at the back as a trough in appearance.

Furthermore, the individual structural elements and / or the carrier substrate are preferably not only made of an electrically insulating material, but preferably also of a thermally insulating material.

A difference compared to the above-mentioned thermopile according to DE 20 2006 003 595 Ul is further that the

Support substrate is flat in itself and has only a three-dimensional surface structure.

The three-dimensional surface structure of the carrier substrate is preferably a microstructure.

This means that the individual structural elements (for example ribs, depressions) have a spacing or a width which lie in the micrometer range or at least in the millimeter range. The spacing and / or the width of the structural elements (e.g., ribs, hollows) may thus be less than 5mm, 2mm, 1mm, 500μm, 250μm, 100μm, 50μm, or even less than 25μm.

On the one hand, this microstructuring of the surface structure of the carrier substrate is advantageous because in this way a large packing density of the thermocouples can be achieved. For example, the area-related packing density of the thermocouples on the carrier substrate can be greater than the learning ^" ² , 10 cm ^{" 2} , 100 cm ² , 1,000 cm ² or even 10,000 cm ² .

On the other hand, the microstructuring of the surface structure of the carrier substrate is advantageous because the processing of the carrier substrate can thereby be carried out very efficiently with conventional patterning methods, which are known, for example, from semiconductor technology.

In addition, it should be mentioned that the individual structural elements of the three-dimensional surface structure of the carrier substrate may, for example, have a triangular or trapezoidal cross-section.

It can already be seen from the above description that a plurality of thermopiles can be arranged on the carrier substrate, which are electrically connected in series one behind the other, wherein the individual thermopiles can each be arranged transversely to the elongated structural elements and next to one another.

The individual thermopiles may in this case contain more than 10, 20, 50 or even more than 100 thermocouples, while a total of more than 10, 20, 50 or even more than 100 such thermopiles can be accommodated on the carrier substrate.

The inventive thermoelectric converter can therefore have more than 100, 500, 1000, 2500, 5000 or even more than 10,000 thermocouples.

Furthermore, the thermoelectric converter according to the invention preferably has an electrically insulating upper layer which covers the carrier substrate with the thermocouples applied thereto on its upper side, while the carrier substrate is preferably covered on its underside by an electrically insulating lower layer.

The topsheet and / or the backsheet are preferably made of a thermally conductive material to thermally contact the thermopile. For example, the topsheet and the backsheet may be made of a ceramic material or a coated metal.

In addition to the thermoelectric converter according to the invention described above, the invention also includes a corresponding manufacturing method, as already apparent from the foregoing description.

In this case, the three-dimensional surface structure of the carrier substrate can be produced, for example, by (micro) injection molding, laser etching or by chemical etching.

In the context of the manufacturing method according to the invention, the conductor layers of the individual thermocouples can be vapor-deposited, sputtered on, printed on, tested on, or galvanically applied, for example, to the three-dimensional surface structure of the carrier substrate, to name but a few possible production methods.

It has already been mentioned above that the individual thermal columns are preferably aligned at right angles to the elongate structural elements (eg ribs, hollows), which is advantageous in the production of a large number of thermopiles. For this purpose, the carrier substrate with the thermopiles applied thereto is in each case between the directly adjacent thermopile in the longitudinal direction of the thermopile divided, so that each separated part contains at least one thermopile. The thermopile on the individual separated parts are then preferably connected again in series electrically in series.

The above-mentioned division of the carrier substrate with the thermopiles applied thereon can be carried out, for example, by etching or by laser irradiation, for which example an ultraviolet laser or a picosecond laser can be used.

Finally, an electrically insulating upper layer is preferably applied to the upper side of the carrier substrate with the thermopiles applied thereon in order to thermally contact the thermoelectric converter.

In addition, an electrically insulating but thermally conductive underlayer is preferably applied to the underside of the carrier substrate for thermal contacting of the thermoelectric converter.

In the context of the invention, the upper layer and / or the lower layer can be adhered, but other attachment options are conceivable within the scope of the invention.

As a material for the upper layer and the lower layer, for example, a ceramic material or coated metal is suitable.

Other advantageous developments of the invention are characterized in the subclaims or are explained in more detail below together with the description of the preferred embodiments of the invention with reference to FIGS. Show it: FIGS. 1A-1E show various successive production stages of a thermoelectric converter according to the invention,

Figure 2 is a perspective view of a thermoelectric transducer according to the invention without the carrier substrate, as well as

FIG. 3 shows the production method according to the invention in the form of a flow chart.

The production method according to the invention will now be described below with reference to the flow chart shown in FIG. 3 and to FIGS. 1A to IE.

In a first step S1, firstly a carrier substrate 1 is provided which consists of an electrically and thermally insulating material and in the simplest case may be plate-shaped.

In a second step S2, a microstructuring of the carrier substrate 1 then takes place to form a three-dimensional surface structure in the carrier substrate 1, the three-dimensional surface structure having a plurality of elongated structural elements 2 in the form of ribs.

The microstructuring of the carrier substrate 1 can be effected for example by hot stamping, micro-injection molding, laser etching or by chemical etching.

It should be mentioned here that the rib-shaped structural elements 2 can each have a continuous cavity 3 in order to increase the thermal conductivity of the rib-shaped structural elements. 2 and thereby improve the functionality of thermocouples applied thereto.

After the microstructuring of the carrier substrate 1 in step S2, the production stage shown in FIG. 1A is present.

It can be seen from FIGS. 1A and 4B that the rib-shaped structural elements 2 each have two lateral flanks 4, 5.

In a further method step S3, a conductor layer 6 is then applied to the side flank 5 of the individual rib-shaped structural elements 2. This application of the conductor layer 6 can take place, for example, by vapor deposition or sputtering, as is schematically indicated in FIG. 1B by the block arrows.

The conductor material for the conductor layer 6 is in this case applied at an angle of incidence α «70 ° obliquely on the side edges 5, for example by sputtering or vapor deposition. This oblique application of the conductor material is advantageous because the individual rib-shaped structural elements 2 shade the other side edges 4, so that the side edges 4 are not coated with the conductor material in this method step.

At the end of method step S3, the production stage shown in FIG. 1B is present.

In a further method step S4, a conductor layer 7 is then also applied to the opposite side flank 4 of the rib-shaped structural elements 2, which is achieved by applying sputtering or vapor deposition can take place, as indicated in Figure IC by the block arrows.

Also, the conductor material for the conductor layer 7 is in this case applied at an angle of incidence α «70 ° obliquely on the side edges 4. This oblique application of the conductor material is again advantageous because the individual rib-shaped structural elements 2 shade the side flanks 5 already coated with the conductor layer 6, so that the side flanks 5 are not coated with the conductor material in this method step.

The two conductor layers 6, 7 each form a leg of a thermocouple, so that the conductor layers 6, 7 overlap at the top of the rib-shaped structural elements 2 and form a contact point. In the same way, the adjacent conductor layers 6, 7 also overlap in the trough between the adjacent rib-shaped structural elements 2 and form a further contact point there.

It is important here that the two conductor layers 6, 7 consist of materials with different thermal forces, so that the immediately adjacent conductor layers 6, 7 each form a thermocouple.

After step S4, the production stage according to FIG.

In a further step S5, the carrier substrate 1 with the thermocouples applied thereto is then divided at right angles to the elongated rib-shaped structural elements 2 along predetermined separating lines 8 in the longitudinal direction of thermal columns 9. The parts formed in this way each contain one of the thermopile 9. After the division of the carrier substrate 1 with the thermopile 9 thereon, the isolated Thermosäu- len 9 are then electrically connected together in a series circuit. For this purpose, corresponding conductor tracks can be arranged on the top layer 10 or on the base 11.

Finally, in a step S6, an electrically and thermally insulating top layer 10 and an electrically and thermally insulating base 11 are glued, the top layer 10 covering the carrier substrate 1 with the thermocouples applied to it at its upper side, while the base 11 covers the carrier substrate 1 covered with the applied thermocouples on its underside.

After step S6, the provisionally final production stage according to FIG. IE is then present, it being possible for further finishing steps to follow within the scope of the production method according to the invention.

However, the production stage according to FIG. IE shows a thermoelectric converter 12 with all the required functional elements.

Figure 2 shows a perspective view of an alternative embodiment of a thermoelectric transducer 13 in an intermediate stage of manufacture without the underlying carrier substrate.

It can be seen that a plurality of conductor layers 14, 15 are applied to the side edges of the rib-shaped structural elements of the carrier substrate. In addition, it can be seen that the carrier substrate with thermopile 16 applied thereto is divided into several parts along certain parting lines 17, the individual parts each containing one of the thermopiles 16.

Alternatively, there is the possibility that FIG. 2 shows an intermediate stage of the production in which the carrier substrate is flat and corrugated-like shaped in order to form the rib-shaped structural elements.

The invention is not limited to the embodiment described above. Rather, a multiplicity of variants and modifications is possible, which likewise make use of the concept of the invention and therefore fall within the scope of protection.

* * * * *

List of reference numbers:

1 carrier substrate

2 structural elements

3 cavity

4 side flank

5 side flank

6 conductor layer

7 conductor layer

8 dividing line

9 thermopile

10 top

11 base

12 thermoelectric converter

13 thermoelectric converter

14 conductor layer

15 conductor layer

16 thermopile

17 dividing line

* * *

Claims

1. thermoelectric converter (12; 13), in particular a thermoelectric generator, with a) a carrier substrate (1) and b) at least one thermopile (9) with numerous thermocouples, which are electrically connected in series behind one another and on the Carrier substrate (1) are applied, characterized in that c) that the carrier substrate (1) has a three-dimensional surface structure with elevations and depressions as structural elements (2).

2. Thermoelectric transducer (12; 13) according to claim 1, characterized in that a) that the individual thermocouples have hot contact points and cold contact points, b) that the hot contact points and the cold contact points arranged alternately on the elevations and in the recesses are.

3. thermoelectric transducer (12; 13) according to any one of the preceding claims, characterized in that a) that the individual structural elements (2) of the three-dimensional surface structure of the carrier substrate (1) are each elongated, b) that the individual thermocouples with their electrical Current direction are each aligned transversely to the elongated structural elements (2) of the carrier substrate (1).

4. Thermoelectric transducer (12; 13) according to claim 3, characterized in that a) that the individual structural elements (2) each have two

Have side edges, b) that the individual thermocouples each have two conductor layers of materials with different thermal forces, and c) that the two conductor layers of the individual thermocouples are each applied to the immediately adjacent side edges of the same structural element.

5. thermoelectric transducer (12; 13) according to any one of the preceding claims, characterized in that a) that the elongated structural elements (2) of the three-dimensional surface structure of the carrier substrate

(1) are aligned substantially parallel to one another, and / or b) that the individual thermocouples are aligned with their electrical current direction at right angles to the elongated structural elements (2) of the carrier substrate (1), and / or c) that the structural elements (2) the three-dimensional surface structure of the carrier substrate (1) is at least partially hollow, and / or d) that the carrier substrate (1) (1) consists of an electrically and thermally insulating material, and / or e) that the carrier substrate ( 1) (1) is flat, and / or f) that the individual structural elements (2) of the three-dimensional surface structure of the carrier substrate (1) each have a triangular, wavy or trapezoidal cross-section.

6. thermoelectric transducer (12; 13) according to any one of the preceding claims, characterized in that a) that on the carrier substrate (1) a plurality of thermopile

(9) are arranged, b) that the thermopile (9) electrically in succession in

C) that the thermopile (9) are each arranged transversely to the elongated structural elements (2) and side by side.

7. Thermoelectric transducer (12; 13) according to one of the preceding claims, characterized in that a) that the thermopile (9) contain more than 10, 20, 50 or more than 100 thermocouples, and / or b) that more than 10, 20, 50 or more than 100 thermopile (9) are arranged on the carrier substrate (1).

8. A thermoelectric converter (12; 13) according to any one of the preceding claims, characterized by a) an electrically insulating upper layer which covers the carrier substrate (1) on its upper side, and / or b) an electrically insulating underlayer, the carrier substrate (1) covers on its underside.

9. thermoelectric transducer (12; 13) according to claim 8, characterized in that the upper layer and / or the lower layer consists of a ceramic material or of coated metal.

10. Manufacturing method for producing a thermoelectric converter, in particular according to one of the preceding claims, comprising the following steps: a) providing a carrier substrate (1), b) applying at least one thermopile (9) with a plurality of thermocouples connected in series in series to the carrier substrate (1), characterized in that c) the carrier substrate (1) has a three-dimensional surface structure with elevations and depressions as structural elements (2) ,

11. Manufacturing method according to claim 10, characterized in that the three-dimensional surface structure of the carrier substrate (1) is produced by one of the following methods: a) injection molding of the carrier substrate (1), b) etching of the carrier substrate (1), in particular laser Etching or chemical etching, c) hot stamping, d) laser sintering, e) three-dimensional printing, in particular piezo-printing.

12. A manufacturing method according to claim 10 or 11, characterized in that the thermocouples are applied by one of the following methods on the three-dimensional surface structure of the carrier substrate (1): a) vapor deposition of conductor layers on the three-dimensional surface structure, b) sputtering of conductor layers the three-dimensional surface structure, c) printing of conductor layers on the three-dimensional surface structure or d) galvanic application of conductor layers on the three-dimensional surface structure, e) spraying.

13. A manufacturing method according to claim 12, characterized in that a) that in the three-dimensional surface structure of the carrier substrate (1) as structural elements (2) elongated depressions and / or elevations are each formed with two side edges, b) that the two conductor layers of the individual Thermocouples are each applied to the immediately adjacent side edges of the elongated structural elements (2).

14. Production method according to one of claims 10 to 13, characterized by the following step:

Dividing the carrier substrate (1) with the thermopiles (9) applied thereon in each case between the directly adjacent thermopiles (9) in the longitudinal direction of the thermopiles (9).

15. Manufacturing method according to claim 14, characterized in that the carrier substrate (1) is divided by one of the following methods: a) etching, b) irradiation with an ultraviolet laser or c) irradiation with a picosecond laser.

16. A manufacturing method according to any one of claims 10 to 15, characterized by the following steps: a) applying an electrically insulating upper layer on the upper side of the carrier substrate (1), and / or b) applying an electrically insulating lower layer to the underside of the carrier substrate (1) ,

17. Production method according to claim 16, characterized in that the upper layer and / or the lower layer is adhered.

18. Production method according to claim 16 or 17, characterized in that the upper layer and / or the lower layer consists of a ceramic material or of coated metal.