THERMOELECTRIC DEVICE

Abstract

A thermoelectric device may include at least two thermoelectric elements manufactured from a thermoelectrically active material. The thermoelectric device may also include at least one conductor path element electrically connecting the at least two thermoelectric elements. The thermoelectric device may further include at least one adapter layer made from a metal and disposed on each of the at least two thermoelectric elements and sandwiched between the respective thermoelectric element and the at least one conductor path element.

Claims

1. A thermoelectric device, comprising: at least two thermoelectric elements manufactured from a thermoelectrically active material; at least one conductor path element electrically connecting the at least two thermoelectric elements; and at least one adapter layer made from a metal and disposed on each of the at least two thermoelectric elements and sandwiched between the respective thermoelectric element and the at least one conductor path element.

2. The thermoelectric device according to claim 1, wherein the metal of the at least one adapter layer has an electrical resistivity that is less than 0.9 Ωcm.

3. The thermoelectric device according to claim 1, wherein the metal of the adaptor layer has an alloy content of less than 10% by weight.

4. The thermoelectric device according to claim 1, wherein the metal of the adapter layer includes one of silver and copper.

5. The thermoelectric device according to claim 1, wherein the adapter layer consists of one of a silver layer and a copper layer.

6. The thermoelectric device according to claim 1, wherein the adapter layer includes at least two layers, of which at least one is applied to the respective thermoelectric element by thermal spraying.

7. The thermoelectric device according to claim 6, wherein one of the at least two layers includes one of copper, nickel, iron, and titanium, and is applied via a thermal spray process.

8. The thermoelectric device according to claim 6, wherein one of the at least two layers: includes one of copper and silver; has a layer thickness of less than 10 μm; and is applied to to another of the at least two layers via one of physical vapour deposition (PVD) and an electroplating process.

9. The thermoelectric device according to claim 1, wherein the at least one adapter layer is sprayed onto the at least two thermoelectric elements.

10. The thermoelectric device according to claim 1, wherein the thermoelectrically active material includes antimony.

11. A thermoelectric generator comprising at least one thermoelectric device having: at least two thermoelectric elements manufactured from a thermoelectrically active material; at least one conductor path element electrically connecting the at least two thermoelectric elements; and at least one adapter layer made from a metal and disposed on each of the at least two thermoelectric elements and sandwiched between the respective thermoelectric element and the at least one conductor path element.

12. A motor vehicle comprising at least one energy supply unit and a thermoelectric generator including at least one thermoelectric device having: at least two thermoelectric elements manufactured from a thermoelectrically active material; at least one conductor path element electrically connecting the at least two thermoelectric elements; and at least one adapter layer made from a metal and disposed on each of the at least two thermoelectric elements and sandwiched between the respective thermoelectric element and the at least one conductor path element.

13. A method for producing a thermoelectric device, comprising: providing at least two thermoelectric elements from a thermoelectrically active material; applying an adapter layer made from a metal to each of the at least two thermoelectric elements; and applying an electrical conductor path to the adapter layers such that the at least two thermoelectric elements are electrically connected to each other electrically.

14. The method according to claim 13, wherein applying the adapter layer is carried out by spraying process.

15. The method according to claim 13, further comprising after providing the at least two thermoelectric elements: roughening a surface of the thermoelectrically active material by one of a blasting process, a grinding process, and an eroding process.

16. The method according to claim 15, wherein the blasting process is a sand blasting process.

17. The method according to claim 14, wherein the spraying process includes one of arc wire spraying and cold gas spraying.

18. The motor vehicle of claim 12, wherein the at least one energy supply unit is a rechargeable battery.

19. The thermoelectric device according to claim 2, wherein the electrical resistivity is less than 0.03 Ωcm.

20. The thermoelectric device according to claim 3, wherein the alloy content is less than 2% by weight.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The FIGURE shows a thermoelectric device.

DETAILED DESCRIPTION

[0034] The single figure shows a thermoelectric device 1, for a thermoelectric generator for example. This has a plurality of thermoelectric elements 2 arranged adjacent to and at a distance to each other along a direction of extension R. In the example scenario of the figure, for the sake of clarity only three such elements 2a, 2b, 2c are shown, adjacent to and at a distance from each other, each of which has in alternating pattern the thermoelectric p-material and n-material familiar to the person skilled in the art, containing antimony (Sb) for example.

[0035] Thermoelectric device 1 may be equipped with a housing 3 made from a metal. In the figure, housing 3 is shown only partially and schematically in the form of two opposing housing walls 3a, 3b, which can be thermally coupled to the hot side H and the cold side K of the generator. In the example of the figure, an electrically insulating layer 9a, 9b is provided between the thermoelectric elements 2 and each of the two opposing housing walls 3a, 3b to electrically insulate the thermoelectric elements 2 from metallic housing 3. The electrically insulating layers 9a, 9b may be made of a ceramic, for example, or some other suitable, electrically insulating material with high thermal conductivity.

[0036] Each thermoelectric element 2 has a first side 5 extending along a transverse direction Q extending transversely to direction of extension R and a second side 6 positioned opposite the first side. Each of the thermoelectric elements 2 is also connected to an adjacent thermoelectric element 2 via at least one conductor path element 4. Conductor path elements 4 may be manufactured from a metal having the lowest possible electrical resistivity. Metals that might be considered for such particularly include copper, nickel, or iron.

[0037] In the case that a given thermoelectric element 2—in the figure, this is the element 2a which is arranged in the middle relative to direction of extension R—has neighbours 2b and 2c both in and counter to the direction of extension R, a first conductor path element 4ab, disposed on the first side 5 of thermoelectric elements 2 serves to create an electrical connection between the given thermoelectric element 2a with its neighbour 2b in direction of extension R. A further, second conductor path element 4ac disposed on the second side 6 of thermoelectric element 2 serves in similar manner to create an electrical connection between element 2a and its neighbour 2c. Thus, individual thermoelectric elements 2a, 2b, 2c are connected to each other electrically in the manner of a series circuit with the aid of conductor path elements 4ab, 4ac. As shown in the figure, first conductor path element 4ab connects the first two sides 5 of the two thermoelectric elements 2a, 2b, second conductor path element 4ac connects the second two sides 6 of the two thermoelectric elements 2a, 2c.

[0038] One adapter layer 7, 8 made of metal is provided on both the first side 5 and on the second side 6 of thermoelectric elements 2a, 2b, 2c, sandwiched between the respective thermoelectric element 2a 2b, 2c and the respective conductor path element 4ab, 4ac. In the example of the figure the metal of the adapter layer is or comprises silver or copper. The former has an electric resistivity of 0.016 Ωcm, the latter 0.017 Ωcm. But silver has proven to be particularly resistant to oxidation. Furthermore, electrical conductor elements 4, 4ab, 4ac may be applied to silver advantageously without using a flux, the muster. It is particularly expedient if the adapter layer consists of a layer of pure silver or a layer of pure copper. Then—apart from impurities in form of a negligible number of foreign atoms—no substances other than silver or copper are contained in the adapter layer. However, in variants of the example other metals which have an electrical resistivity of less than 0.9 Ωcm, preferably less than 0.2 Ωcm, most preferably less than 0.03 Ωcm, are possible. Such resistance values may be achieved for example if metals with very low or even no alloy content are used. Conceivable is an alloy content of less than about 10% by weight, preferably less than 5% by weight, most preferably less than 2% by weight.

[0039] In order to apply adapter layers 7, 8 to the thermoelectric elements 2, 2a, 2b, 2c with good adhesion properties, it is recommended to use a spray process, for example arc wire spraying or cold spraying. In cold spraying, the metallic coating powder only has to be heated to a temperature of a few 100° C., so that the mechanical stresses induced by the temperature difference between the coating powder and the surface to be coated in the cooling process that follows the heating process are insignificant.

[0040] The respective first and second sides 5, 6 of the thermoelectric elements 2, 2a, 2b, 2c may be roughened by means of a blasting method, for example a sand blasting method, or a grinding method, before the adapter layers 7, 8 are applied.

[0041] A joining material applied in a subsequent step may key well mechanically in the sprayed and roughened adapter layers 7, 8. Of course, not all of the adapter layers 7, 8 must consist of silver, but the desired roughness of the adapter layer 7, 8 overall is also achieved with a first sprayed layer of a material that is less expensive than silver, such as nickel, copper, iron or titanium with a low electrical resistivity, to which a second thin layer is then applied, made of silver or even of copper, by means of PVD, electroplating or brush plating, for example.