Abstract
A thermoelectric module may include a plurality of thermoelectric elements arranged spaced apart from one another between a hot-side substrate and a cold-side substrate. A plurality of conductor bridges may electrically interconnect the plurality of thermoelectric elements and may contact at least one electric connection. The at least one electric connection may include a contact element that is pre-stressed via a pre-stressing arrangement and lies against at least one conductor bridge of the plurality of conductor bridges.
Claims
1. A thermoelectric module, comprising: a plurality of thermoelectric elements arranged spaced apart from one another between a hot side and a cold side; a plurality of conductor bridges for electrically interconnecting the plurality of thermoelectric elements and for contacting with at least one electric connection; a hot-side substrate defining the hot side; a cold-side substrate defining the cold side; wherein the at least one electric connection includes a contact element, and wherein the contact element is pre-stressed via a pre-stressing arrangement and lies against at least one conductor bridge of the plurality of conductor bridges.
2. The module according to claim 1, wherein the pre-stressing arrangement pre-stresses the contact element against the at least one conductor bridge in a direction of one of the hot-side substrate and the cold-side substrate and rests against the other of the hot-side substrate and the cold-side substrate.
3. The module according to claim 2, wherein the pre-stressing arrangement rests against the other of the hot-side substrate and the cold-side substrate parallel to a distance direction of the hot-side substrate and the cold-side substrate aligned to the contact element.
4. The module according to claim 2, wherein the pre-stressing arrangement includes a support element, the support element being supported against the other of the hot-side substrate and the cold-side substrate.
5. The module according to claim 4, wherein the support element is guided in a longitudinally adjustable manner on the contact element.
6. The module according to claim 4, further comprising a telescopic guide disposed between the support element and the contact element.
7. The module according to claim 4, wherein the pre-stressing arrangement further includes a spring element arranged to rest on one side against the support element and on another side against the contact element.
8. The module according to claim 7, wherein the spring element is arranged centrically to a straight connection line, and wherein the straight connection line leads directly from a contact point the contact element lies against the at least one conductor bridge to a support point where the support element rests against the other of the hot-side substrate and the cold-side substrate.
9. The module according to claim 6, wherein the pre-stressing arrangement further includes a spring element arranged in the telescopic guide.
10. The module according to claim 4, wherein the pre-stressing arrangement further includes a contact lever and a support lever mounted swivellably to one another about a swivel axis running perpendicularly to the distance direction, and wherein the contact element is disposed on the contact lever and the support element is disposed on the support lever.
11. The module according to claim 10, wherein the pre-stressing arrangement further includes a spring element supported in a pre-stressed manner on the contact lever and on the support lever on a side of the swivel axis facing away from the contact element and from the support element.
12. The module according to claim 10, wherein at least one of the contact lever and the support lever includes a connection point for connecting an electric cable disposed at an end remote from the contact element and from the support element.
13. The module according to claim 4, wherein the support element includes a projecting pin disposed on an outer side facing away from the one of the hot-side substrate and the cold-side substrate, and wherein the projecting pin engages into a pin mount disposed on the other of the hot-side substrate and the cold-side substrate.
14. The module according to claim 1, further comprising a housing, wherein the hot-side substrate and the cold-side substrate define a component of the housing and wherein the housing contains a hermetically closed interior and the plurality of thermoelectric elements are arranged in the hermetically closed interior.
15. The module according to claim 1, wherein at least one of the hot-side substrate is a component of a wall of a hot channel for directing a heating fluid and the cold-side substrate is a component of a wall of a cooling channel for directing a cooling fluid.
16. The module according to claim 1, wherein the pre-stressing arrangement pre-stresses the contact element against the at least one conductor bridge in a direction of the hot-side substrate and rests against the cold-side substrate.
17. The module according to claim 16, wherein the pre-stressing arrangement includes a support element supported against the cold-side substrate.
18. The module according to claim 17, further comprising a telescopic guide disposed between the support element and the contact element.
19. The module according to claim 18, wherein the pre-stressing arrangement further includes a spring element arranged in the telescopic guide.
20. A thermoelectric module, comprising: a first substrate and a second substrate; a plurality of thermoelectric elements arranged spaced apart from one another between the first substrate and the second substrate, wherein the first substrate is one of a hot-side substrate and a cold-side substrate, and the second substrate is the other of the hot-side substrate and the cold-side substrate; at least one electric connection; a plurality of conductor bridges arranged to electrically interconnect the plurality of thermoelectric elements and to contact the at least one electric connection; the at least one electric connection including a contact element, wherein the contact element is pre-stressed via a pre-stressing arrangement and lies against at least one conductor bridge of the plurality of conductor bridges; and wherein the pre-stressing arrangement pre-stresses the contact element against the at least one conductor bridge in a direction towards the first substrate and rests against the second substrate.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0060] There are shown, respectively diagrammatically, FIGS. 1 to 18 respectively a highly simplified sectional view of a thermoelectric module in different embodiments.
DETAILED DESCRIPTION
[0061] The different embodiments described below with the aid of FIGS. 1 to 18 are basically able to be combined with one another as desired, in so far as this is expedient. In addition, the embodiments belong to three basic aspects of the present invention, which can likewise be combined with one another as desired, in so far as this is expedient. The second of these aspects has several sub-aspects, which likewise are able to be combined with one another as desired, in so far as this is expedient.
[0062] According to FIGS. 1 to 18, a thermoelectric module 1 comprises a plurality of thermoelectric elements 2. In the illustrations, precisely four such thermoelectric elements 2 are shown, purely by way of example. It is clear that such a module 1 can basically have any desired number of such thermoelectric elements 2, which are preferably arranged at least two-dimensionally, therefore not only along the plane of the drawing, but also perpendicularly thereto. The thermoelectric elements 2 are arranged spaced apart from one another between a hot side 3 of the module 1 and a cold side 4 of the module 1. Furthermore, the module 1 has a plurality of conductor bridges 5, which serve for the electrical interconnecting of the thermoelectric elements 2 and for the connecting of electrical connections 6, of which per module 1 at least two are present, of which, however, respectively only one is illustrated in FIGS. 1 and 16 to 18. The conductor bridges 5 associated with or respectively facing the hot side 3 can also be designated in the following by 5′. The conductor bridges 5 associated with or respectively facing the cold side 4 can also be designated in the following by 5″. The conductor bridge 5 provided for connecting an electrical connection 6 can also be designated in the following by 5′″.
[0063] The hot side 3 is formed by a hot-side substrate 7. The cold side 4 is formed by a cold-side substrate 8. In the example of FIG. 2 the two substrates 7, 8 are produced respectively from an electrically insulating material, such as for example from a ceramic. In all other embodiments, the substrates 7, 8 are produced from an electrically conductive material, preferably from a metal, in particular high-grade steel, and on their inner side 9 or respectively 10 facing the thermoelectric elements 2, they are equipped with an electrical insulation 11, which forms a component of the respective substrate 7, 8.
[0064] The conductor bridges 5 can basically be produced from any desired electrically and thermally conductive material. According to a first aspect of the present invention, at least the conductor bridges 5 associated with one of the substrates 7, 8 have respectively a bridge body 12, which is configured so as to be thermally and electrically conductive and elastically deformable. Expediently, both the conductor bridges 5′, which as associated with the hot side 13, and also the conductor bridges 5″, which are associated with the cold side 4, are respectively equipped with such a bridge body 12.
[0065] According to FIG. 1, the bridge bodies 12 can lie directly against the respective substrate 7, 8, in particular against its insulation 11. In the example of FIG. 2, the bridge bodies 12 rest respectively via a metal coating 13 against the respective substrate 7, 8. The metal coating 13 can be formed here on the respective bridge body 12 or on the respective substrate 7, 8.
[0066] In the example of FIG. 3, the respective conductor bridge 5 has on the associated bridge body 12 both on an outer side facing the respective substrate 7, 8 and also on an inner side facing the respective thermoelectric element 2 respectively a metal coating 13. In addition, in FIG. 3, it is indicated at the two bridge bodies 12 arranged on the right that the respective metal layer 13 can also be configured so as to be circumferential, so that ultimately the entire surface of the bridge body 12 is formed by the metal layer 13.
[0067] According to FIG. 4, the respective conductor bridge 5 can have a metallic conducting body 14 on its inner side facing the thermoelectric elements 2. The conducting body 14, for example a piece of wire, which has here expediently a rectangular cross-section, is arranged here outside the bridge body 12 between the two thermoelectric elements 2, which are electrically connected to one another by the respective conductor bridge 5. The respective conducting body 14 is electrically connected to the respective bridge body 12. In the example of FIG. 4, this takes place by a contacting of the conducting body 14 with the metal layer 13. In particular, the conducting body 14 can be connected, preferably in a materially bonded manner, to the metal layer 13. Primarily, a soldered connection is conceivable. In the example of FIG. 4, the respective conducting body 14 is arranged spaced apart from the two thermoelectric elements 2, which are electrically connected to one another by the respective conductor bridge 5. In FIG. 4, corresponding clearances or gaps can be seen, which are not designated in further detail. Expediently, the respective conducting body 14 extends only between these two thermoelectric elements 2, which are electrically connected to one another by the associated conductor bridge 5, along the associated bridge body 12. Preferably, the respective conducting body 14 extends here only over the entire width of the bridge body 12 and is oriented here transversely to the longitudinal direction of the bridge body 12. In the sectional views shown here, the straight-lined conducting bodies 14 extend with their longitudinal extent perpendicularly to the plane of the drawing. The longitudinal direction of the associated bridge bodies 12 lies in the plane of the drawing.
[0068] The bridge body 12 is expediently formed by a graphite film, which can be the case for example in the embodiments of FIGS. 1 to 6 and 8 to 18. Purely by way of example, in FIG. 7 a different embodiment is indicated, in which the respective bridge body 12 is formed by a porous metal structure 15. It is clear that basically also in the other embodiments the bridge body 12 can be formed by such a metal structure 15. The porous metal structure 15 is formed here expediently by a member of the group of metal braiding, metal pads, metal mesh, knitted wire mesh, metal foam, metal textile or of any desired combination of two or more members of this group.
[0069] In so far as the respective bridge body 12 according to FIGS. 3 and 4 has the metal coating 13 on its inner side facing the thermoelectric elements 2, the bridge body 12 can be securely connected via the metal coating 13, preferably in a materially bonded manner, to the respective thermoelectric elements 2.
[0070] Irrespective of whether or not such a metal coating 13 is present, provision can be made according to another embodiment that the respective conductor bridge 5, equipped with the bridge body 12 and in an extreme case formed by the bridge body 12, lies loosely against the respective substrate 7, 8. In particular here the respective bridge body 12 can lie loosely directly against the respective substrate 7, 8. In particular, the respective bridge body 12 here can lie loosely directly against the respective substrate 7, 8. Such a direct contacting is shown in FIG. 1. There, the bridge body 12 in fact lies against the respective insulation 11, but this forms a component of the respective substrate 7, 8.
[0071] In contrast, in so far as a secure fixing between the respective conductor bridge 5 and the respective substrate 7, 8 is desired, this can be realized for example by the metal coating 13 on the bridge body 12, which is formed for this at least on an outer side of the bridge body 12 facing the respective substrate 7, 8. Expediently, the insulation 11 of the respective substrate 7, 8 can then also be metallized or can be provided with a metal layer, which is indicated purely by way of example only in FIGS. 3 to 7 and is designated by 16. Therefore, a materially bonded connection, preferably a soldered connection, can also be realized here. The same applies to the embodiment shown in FIG. 7, in which the porous metal structure 15 can be securely connected directly to the metal layer 16 of the insulation 11.
[0072] In the examples of FIGS. 5 and 6, the respective conductor bridge 5 is equipped furthermore with a metal bridge 17, which is provided in addition to the bridge body 12 and which is situated here on an inner side of the respective bridge body 12 facing the thermoelectric elements 2. The metal bridge 17 extends expediently over the entire length of the associated bridge body 12 and is therefore ultimately arranged between the bridge body 12 and axial face sides of the two thermoelectric elements 2, with which the respective bridge body 12 or respectively the respective conductor bridge 5 is associated. The said face sides of the thermoelectric elements 2 are facing the respective substrate 7, 8. In the example of FIG. 5, the respective metal bridge 17, which of course consists of a metallic material, is directly in contact with the face sides of the two thermoelectric elements 2. Expediently, a secure, preferably materially bonded, connection is also preferred here.
[0073] In contrast thereto, FIG. 6 shows an embodiment in which the respective metal bridge 17 is supported on the respective face side via at least one further bridge body 12′, which is likewise configured so as to be thermally and electrically conductive and elastically deformable. In the example of FIG. 6, two separate further bridge bodies 12′ are provided here per metal bridge 17. Basically, however, a common, continuous further bridge body 12′ is conceivable. In FIG. 6, in the case of the conductor bridges 5″, which are associated with the cold-side substrate 8, provision is made that the bridge body 12 lies directly′ against the cold-side substrate 8 and directly against the metal bridge 17. Furthermore, provision is made there that the further bridge bodies 12′ on the one hand lie respectively directly against the thermoelectric elements 2 and on the other hand against the metal bridge 17. Depending on the material of the bridge body 12 or respectively of the further bridge body 12′, a loose abutment or a, preferably materially bonded, fixing comes into consideration here. In FIG. 6, in the case of the three left-hand thermoelectric elements 2, provision is made that the conductor bridges 5′ associated with the hot-side substrate 7′, are still configured so that the associated bridge bodies 12 and also the further bridge bodies 12′ are equipped respectively with the metal coating 13 on their outer side facing the hot-side substrate 7, and also with the metal coating 13 on their inner side facing the cold-side substrate 8. Therefore, in particular an embodiment is possible in which the bridge body 12 is fastened via the metal coating 13, and the further metal layer 16, provided if applicable on the insulation 11, on the hot-side substrate 7. Furthermore, these bridge bodies 12 are also fastened on the metal bridge 17 via the metal coating 13. The further bridge bodies 12′ are fastened here on the one hand on the respective thermoelectric element 2 and on the other hand on the respective metal bridge 17 respectively via the metal coating 13.
[0074] Expediently the module 1 has, moreover, a housing 18, which is only partially illustrated in FIGS. 1 to 18 and which contains an interior 19 which is hermetically closed to the exterior. The thermoelectric elements 2 are arranged in this interior 19. Expediently, two walls of the housing 19, facing away from one another or respectively remote from one another, are formed by the substrates 7, 8. In an alternative type of construction, the hot-side substrate 7 can form a component of a wall of a heating channel, in which a heating fluid is directed. Additionally or alternatively, the cold-side substrate 8 can form a component of a wall of a cooling channel, in which a coolant is directed. Hereby, the modules 1 can be integrated into a heat exchanger in a particularly simple manner.
[0075] According to FIGS. 8 to 15, according to a second aspect of the present invention, the module 1 can have, furthermore, an electrically insulating mount 20, which serves for the positioning of the thermoelectric elements 2 between the substrates 7, 8. Such a mount 20 can basically be provided in all the embodiments which are shown here. In so far as a housing 18 is present, the mount 20 is arranged in the interior 19. The mount 20 has a separate through-opening 21 for each thermoelectric element 2, into which through-opening the respective thermoelectric element 2 is inserted. Expediently, an internal cross-section of the respective through-opening 21 is coordinated with an external cross-section of the respective thermoelectric element 2 so that a secure fixing in position occurs for the respective thermoelectric element 2 in the through-opening 21 on the mount 20.
[0076] Such a mount 20 can come into use for example when the conductor bridges 5′, proximal to the hot-side substrate 7, lie loosely against the hot-side substrate 7 or respectively against its insulation 11 and/or when the conductor bridges 5″, proximal to the cold-side substrate 8, lie loosely against the cold-side substrate 8 or respectively against its insulation 11. This corresponds to a first sub-aspect of this second aspect of the invention. In particular, thereby a block designated by 22 in FIG. 8, can be created, which is mounted as it were in a floating manner between the substrates 7, 8. Alternatively thereto, the mount 20 itself can be securely connected via suitable connection points 23 to the hot-side substrate 7 and/or to the cold-side substrate 8. For example, the mount 20 is fastened to the respective substrate 7, 8 only in a circumferential region 24, which surrounds the thermoelectric elements 2 in the circumferential direction.
[0077] FIG. 9 shows a second sub-aspect of this second aspect of the invention. For this, provision is made that the mount 20 has a hot region 25 facing the hot-side substrate 7, and a cold region 26 facing the cold-side substrate 8, which are produced from different materials. Accordingly, the hot region 25 is produced from a first material, which can be, for example, a ceramic. In contrast thereto, the cold region 26 is produced from a second material, which is different from the first material, and which can be, for example, a plastic. In the example of FIG. 9, the hot region 25 is formed by at least a first mount portion 27, whilst the cold region 26 is formed by at least a second mount portion 28. The different holding parts 27, 28 are fitted against one another. In the example of FIG. 9, a plug connection 64 is formed between the two mount portions 27, 28, which plug connection has cone-shaped or wedge-shaped projections on the first mount portion 27, and cone-shaped or wedge-shaped depressions, complementary thereto, on the second mount portion 28. The first mount portion 27 and second mount portion 28 are configured in FIG. 9 so that the above-mentioned through-openings 21 are formed exclusively on the second mount portion 28 or respectively on the hot region 26.
[0078] FIG. 10 shows a third sub-aspect of the second aspect of the present invention. Here, the mount 20 for the conductor bridges 5′ proximal to the hot-side substrate 7, and/or for the conductor bridges 5″ proximally to the cold-side substrate 8, has respectively a recess 29, in which the conductor bridges 5 are arranged in a recessed manner. A specific embodiment is shown here, in which the recesses 29 are dimensioned so that the conductor bridges 5 are arranged therein in a recessed manner to such an extent that they respectively terminate in a flush manner with an outer side 30 of the mount 20 facing the respective substrate 7, 8. Hereby, said outer side 30 lies flat against the respective substrate 7, 8.
[0079] According to FIGS. 11 and 12, in accordance with a fourth sub-aspect of the second aspect of the present invention, provision can be made that the mount 20 has a hot part 31, proximal to the hot-side substrate 7, and a cold part 32, proximal to the cold-side substrate 8. The previously mentioned through-openings 21 are formed here both in the hot part 31 and also in the cold part 32. Furthermore, it is shown in FIGS. 11 and 12 that in the hot part 31 and in the cold part 32 likewise the recesses 29, explained with reference to FIG. 10, can be formed.
[0080] An embodiment is advantageous, in which the hot part 31 is fastened to the hot-side substrate 7, whereas the cold part 32 is adjustable relative to the hot part 31 along the thermoelectric elements 2. In other words, in this structural form, the cold part 32 is not fastened to the cold-side substrate 8. In the reverse type of construction, on the other hand, the cold part 32 is fastened to the cold-side substrate 8, whereas the hot part 31 is not fastened to the hot-side substrate 7, but rather is arranged so as to be adjustable relative to the cold part 32 along the thermoelectric elements 2. In FIG. 11, purely by way of example, a guide 33 is shown, which improves the adjustability of hot part 31 and cold part 32 relative to one another. In FIG. 12, on the other hand, a connection 34 is shown between the hot part 31 and the cold part 32, which can be configured so as to be articulated and/or elastic, and which in particular can contain at least one predetermined breaking point 35. The articulated or elastic connection 34 can permit the desired relative movements. Likewise, the predetermined breaking point 35 can break in the case of sufficient force, and can then enable the desired relative adjustment.
[0081] As can be seen from FIGS. 11 and 12, furthermore in the region of the thermoelectric elements 2 an intermediate space 36 can be formed between the hot part 31 and the cold part 32, in which intermediate space the hot part 31 and cold part 32 are spaced apart from one another. In the case of a relative adjustment of the hot part 31 with respect to the cold part 32, this distance reduces.
[0082] In another embodiment, provision can be made that on the one hand the hot part 31 is securely connected to the hot-side substrate 7, whereas on the other hand the cold part 32 is securely connected to the cold-side substrate 8. Additionally or alternatively, provision can be made that the hot part 31 corresponds to the above-mentioned hot region 25 and accordingly is produced from the first material, whereas the cold part 32 corresponds to the cold region 26 and is produced from the second material.
[0083] In the examples of FIGS. 9 and 13 to 15, a further embodiment is shown, which corresponds to a fifth sub-aspect of the second aspect of the present invention. Accordingly, the mount 20 has a positioning region 37, in which the through-openings 21 are exclusively formed. This positioning region 37 is supported via at least one holding region 38 on at least one of the substrates 7, 8, preferably on both substrates 7, 8. In these embodiments, it is noteworthy that the positioning region 37 has a greater distance from the hot-side substrate 7 than from the cold-side substrate 8. Expediently, the distance of the positioning region 37 from the hot-side substrate is at least twice as great as from the cold-side substrate 8. In so far as only a common holding region 38 is provided, this can be configured as a frame which surrounds in a closed manner in circumferential direction the region in which the thermoelectric elements 2 are arranged. Alternatively, a plurality of separate holding regions 38 can also be provided, e.g. in the four corners of a rectangular module 1, which are likewise arranged outside the region of the thermoelectric elements 2. The holding region(s) 38 extend therefore in the previously mentioned circumferential region 24.
[0084] The holding region(s) 38 can be securely connected to the respective substrate 7, 8 in a different suitable manner. FIG. 9 shows plug connections 39 between the holding regions 38 and the hot-side substrate 7. FIG. 9 shows in addition clip connections 40 between the holding regions 38 and the cold-side substrate 8. FIG. 13 shows clip connections 40 between the holding regions 38 and the hot-side substrate 7 on the one hand and the cold-side substrate 8 on the other hand. FIG. 14 shows screwed connections 41 between the holding regions 38 and the hot-side substrate 7 and pin connections 42 between the holding regions 38 and the cold-side substrate 8. In FIG. 15, on the other hand, adhesive connections 43 are shown, by which the holding regions 38 are fixed to the hot-side substrate 7 and to the cold-side substrate 8.
[0085] As already explained above, FIGS. 1 and 16 to 18 show one of at least two electric connections 6 of the module 1. Here, according to FIG. 1, it is basically possible to connect the electric connection 6 directly to one of the conductor bridges 5, here to the conductor bridge 5′″, in so far as the material of this conductor bridge 5′″ is suitable for such a connection. Preferably, soldered connections come into use here.
[0086] The same also applies to the embodiment shown in FIG. 16, in which the connection 6 is ultimately realized by means of a large-volume soldering point 44, by which a contact element 45 of the connection 6 is securedly connected mechanically in an electrically conductive manner to the respective conductor bridge 5′″ and/or to a metal coating 13 of the insulation 11. On the contact element 45 a connection element 46 is formed, which defines a connection point 47 for connecting an electric cable.
[0087] In FIGS. 17 and 18, another embodiment is now shown for the realization of such an electric connection 6, which represents a third aspect of the present invention. For this, the electric connection 6 comprises a pre-stressing arrangement 48, which presses the contact element 45 against the respective conductor bridge 5′″ by means of a pre-stressing force 49. Accordingly, the contact element 45 lies in a pre-stressed manner against an inner side of the respective conductor bridge 5, facing the thermoelectric elements 2, which is also designated here by 5′″. The pre-stressing force 49 is oriented here parallel to the distance direction 65 of the substrates 7, 8.
[0088] In the examples of FIGS. 17 and 18, the contact element 45 is equipped, for this, with a contact contour 50, which has elevations which taper and accordingly enable a linear and/or punctiform contacting with the conductor bridge 5. In the sectional views which are shown, a sawtooth-shaped profile can be seen. Accordingly, the contact contour 50 has a plurality of parallel, tapering webs and/or a plurality of tapering pyramids or cones. In so far as here a soft material is used for the conductor bridge 5 or respectively its bridge bodies 12, the contact contour 50 can penetrate into the surface of the conductor bridge 5 and can thereby produce a particularly intimate contact.
[0089] The pre-stressing arrangement 48 pre-stresses the contact element 45 in the direction of the one substrate, here in the direction of the hot-side substrate 7, against the respecting conductor bridge 5 and rests here against the other substrate, here against the cold-side substrate 8. In addition, the pre-stressing arrangement 48 rests parallel to the distance direction of the substrates 7, 8 aligned to the contact element 45 against the cold-side substrate 8.
[0090] Expediently, the pre-stressing arrangement 48 has a support element 51, which is supported against the cold-side substrate 8. The support element 51 rests here in a support point 52 on the cold-side substrate 8. In contrast thereto, the contact element 45 rests in a contact point 53 on the respective conductor bridge 5.
[0091] In the embodiment shown in FIG. 17, the support element 51 and the contact element 45 are guided on one another in a longitudinally adjustable manner. In particular, a telescopic guide 54 is formed for this between the support element 51 and the contact element 45. This longitudinal guide or respectively the telescopic guide 54 is oriented here parallel to the pre-stressing force 49, which in turn extends parallel to the distance direction 65 of the two substrates 7, 8.
[0092] In both embodiments, the pre-stressing arrangement 48 has a spring element 55, which is compressed for generating the pre-stressing force 49. Therefore this is a compression spring.
[0093] In the example of FIG. 17, the spring element 45 is positioned so that it rests on the one hand against the support element 51 and on the other hand against the contact element 45. In addition, the spring element 55 is aligned here centrically to an imaginary straight connection line 56, which leads directly from the contact point 53 to the support point 52. This straight connection line 56 extends here parallel to a distance direction 65 of the substrates 7, 8, in which the substrates 7, 8 are spaced apart from one another. In particular, the spring element 55 is arranged here within the telescopic guide 54.
[0094] In the example of FIG. 18, the pre-stressing arrangement 48 has a contact lever 57, which has the contact element 45, and a support lever 58, on which the support element 51 is formed. The contact lever 57 and support lever 58 are mounted swivellably to one another about a swivel axis 59. A corresponding bearing is designated here by 60. The swivel axis 59 extends perpendicularly to the distance direction 65 of the substrates 7, 8 and in FIG. 18 stands perpendicularly on the plane of the drawing. The spring element 55 is supported on the contact lever 57 and on the support lever 58 on a side of the swivel axis 59 facing away from the contact element 45 and from the support element 51, and namely in a compressed state, in order to generate the pre-stressing 49. The connection point 47 is arranged here at an end 61 of the connection lever 57 remote from the connection element 45. A guide 63 for the spring element 55 is formed on the support lever 58 at an end 62 remote from the support element 52.
[0095] In the embodiments shown in FIGS. 17 and 18, the support element 51 has in addition a pin 66, which projects on a side of the support element 51 facing away from the hot-side substrate 7, and engages into a pin mount 67 formed on the cold-side substrate 8. Whereas the contact element 45 and the possibly present contact lever 57 consist of an electrically conductive material, preferably of a metal, the support element 51 and the possibly present support lever 58 can consist of an electrically insulating material, preferably of a plastic.
