WO2017046482A1

WO2017046482A1 - Hydraulic coupling and thermoelectric device intended, in particular, for generating an electric current in a motor vehicle, including such a hydraulic coupling

Info

Publication number: WO2017046482A1
Application number: PCT/FR2016/052254
Authority: WO
Inventors: Kamel Azzouz; Patrick Boisselle; Cédric DE VAULX; Véronique MONNET; Ambroise SERVANTIE
Original assignee: Valeo Systemes Thermiques
Priority date: 2015-09-15
Filing date: 2016-09-09
Publication date: 2017-03-23
Also published as: FR3041058B1; FR3041058A1

Abstract

The present invention relates to a hydraulic coupling for a thermoelectric device comprising a plurality of thermoelectric modules (2), each thermoelectric module (2) including at least one plurality of cylindrical thermoelectric elements (7p, 7n) comprising a central circular recess receiving a central tube (11), a first fluid being intended for circulating through the central tube (11) and a second fluid being intended for circulating around the outer periphery, a so-called inner tubular electrode (14) rigidly connected to an inner surface of each thermoelectric element (7p, 7n), a so-called outer tubular electrode (12) rigidly connected to an outer surface of each thermoelectric element (7p, 7n), said coupling including a body (17) provided with means for establishing fluid communication between the outlet of the central tube (11) of a first thermoelectric module (2) and the intake of a central tube (11) of a second thermoelectric module (2) and at least two electrical contact mountings (24) rigidly connected to said body (17).

Description

FIELD OF THE INVENTION The present invention relates to a hydraulic coupling and a thermoelectric device, in particular for generating an electric current in a motor vehicle. , including such a hydraulic connection. In the automotive field, has already been proposed electric thermo devices, also called electric thermo generators or TEG according to the acronym "ThermoElectric Generator", using so-called electric thermo elements, to generate an electric current in the presence of a temperature gradient between two of their opposite faces according to the phenomenon known as the Seebeck effect. These devices comprise a stack of first tubes, intended for the circulation of the exhaust gases of an engine, and second tubes, intended for the circulation of a heat transfer fluid of a cooling circuit. The electrical thermo elements are sandwiched between the tubes so as to be subjected to a temperature gradient from the temperature difference between the hot exhaust gases and the cold cooling fluid.

Such devices are particularly interesting because they make it possible to produce electricity from a conversion of the heat coming from the exhaust gases of the engine. I ls thus offer the possibility of reducing the fuel consumption of the vehicle by replacing, at least partially, the alternator usually provided therein to generate electricity from a belt driven by the crankshaft of the vehicle. engine. Thermoelectric devices having a plurality of thermoelectric modules have already been developed, each module comprising annular-shaped thermoelectric elements in which the first fluid and the second fluid circulate transversely relative to one another. Such a thermoelectric module comprises a plurality of annular-shaped thermoelectric elements arranged in the longitudinal extension of one another in a coaxial manner, with for example an alternation of N-type thermoelectric elements and thermoelectric elements. P-type electrical elements. Each thermoelectric element has fins extending from the outer periphery, transversely and radially. These fins, usually obtained in aluminum or stainless steel and crimped on the outer diameter of the rings of the thermoelectric elements, make it possible to promote heat exchange with the hot exhaust gases flowing through said fins, a fluid cold circulating in the center of the electric thermo elements, and extract the maximum heat of the exhaust gases to transfer it to thermoelectric materials.

Said modules thus comprise electric thermo elements which are assembled in the form of cylindrical rods and are distributed in a cylindrical enclosure so that the hot exhaust gases circulate freely between each module while a heat transfer fluid of a cooling circuit circulates in the center of the electric thermo elements. These cylindrical configuration devices have the disadvantage of having separate parts to perform the functions of hydraulic and electrical connectors of the various cylindrical rods thus increasing the size of these devices. The invention proposes to improve the situation and relates for this purpose a hydraulic connection for thermoelectric device comprising a plurality of electric thermo modules, each thermoelectric module comprising at least a plurality of cylindrical thermoelectric elements comprising a central circular recess receiving a central tube, said electric thermo elements being capable of generating an electric current under the action of a temperature gradient exerted between a first defined external face by an outer periphery surface and a second inner face defined by an inner periphery surface, a first fluid being adapted to flow through the central tube and a second fluid being adapted to circulate around the outer periphery, said fitting comprising a body provided with means for placing in fluid communication the outlet of the central tube of a first thermoelectric module with the inlet of a central tube of a second thermoelectric module and at least one or even two supports for electrical contacts integral with said body. It is understood that such a hydraulic connection combines electrical and hydraulic functions thus reducing the size of components providing these functions and reduce costs by providing a single room for these two functions. According to different embodiments of the invention, taken together or separately:

the body is obtained in a dielectric material,

the body is obtained in a dielectric plastic,

the dielectric plastic consists of polyamide or polypropylene,

the one or more electrical contact supports consist of threaded rods obtained in a plastic material,

the threaded rods are secured to the body of the hydraulic coupling by overmolding,

the threaded rods are secured to the body of the hydraulic coupling by gluing, the threaded rods are secured to the body of the hydraulic coupling by screwing said rods into tapped holes in said body, the body is constituted by a cylindrical crown-shaped housing, having two side walls which have the shape of a disc provided with a central circular hole, a cylindrical inner wall and a cylindrical outer wall, holes made on one of the side walls for receiving the central tubes of the thermoelectric modules, said holes being provided with sealing means, at least one internal partition defining at least one so-called inlet chamber and a so-called exhaust chamber, and at least one intake manifold opening into the intake chamber and an exhaust manifold opening into the exhaust chamber,

the intake and exhaust pipes extend radially from the outer body peripheral wall,

the threaded rods extend radially from the outer peripheral wall of the body,

the sealing means consist of O-rings positioned in the holes receiving the central tubes,

the holes receiving the central tubes are uniformly distributed around the body.

The invention also relates to a thermoelectric device comprising at least a plurality of electric thermo modules, each thermoelectric module comprising at least a plurality of cylindrical thermoelectric elements comprising a central circular recess receiving a central tube, said thermoelectric elements being susceptible to generate an electric current under the action of a temperature gradient exerted between a first so-called outer face defined by an outer periphery surface and a second inner so-called face defined by an inner periphery surface, a first fluid being intended to circulate through the central tube and a second fluid being intended to flow around the outer periphery, and at least one or even two hydraulic connections according to the invention to put in fluid communication the outlet of the central tube of a first thermoelectric module with the inlet of a central tube of a second electric thermo module.

According to one aspect of the invention said module comprises a so-called inner tubular electrode integral with the inner face of each thermoelectric element, an outer tubular electrode secured to the outer face of each thermoelectric element.

Advantageously, said device is configured to be positioned in a motor vehicle exhaust gas conduit so that said gases circulate in the envelope, said gases defining the second fluid. The invention will be better understood in the light of the following description which is given only as an indication and which is not intended to limit it, accompanied by the appended drawings among which:

FIG. 1 is a perspective view in longitudinal section of the thermoelectric device according to the invention; FIG. 2 is a perspective view of a thermoelectric module of the thermoelectric device according to the invention, FIG. perspective view of a hydraulic and electrical connection of the thermoelectric device according to the invention, FIG. 4 is a schematic representation of the connection of two electric thermo modules of the thermoelectric device according to the invention,

Figure 5 schematically illustrates, in cross section, an example of a thermoelectric device according to the invention.

In the figures, identical or similar elements bear the same references. As illustrated in FIG. 1, the invention relates to a thermoelectric device 1 comprising a plurality of modules 2, as will be detailed below, positioned circularly and extending parallel to the interior of a tubular casing 3 of which the ends are closed by an intake manifold 4 of a first fluid, in this case hot exhaust gases, and an intake manifold 5 of a second fluid, namely a heat transfer fluid of a circuit cooling, and respectively by an exhaust manifold 6 of said first and second fluids. The casing 3 has a circular cross section and the modules 2 of thermoelectric elements are positioned circularly inside said casing 3 about the axis of revolution of said casing 3.

Referring to Figures 1 and 2, each module 2 comprises a plurality of electric thermo elements 7n, 7p, cylinder-shaped or straight prism and having a central recess, capable of generating an electric current under the action of a temperature gradient exerted between a first so-called outer face defined by an outer periphery surface and a second so-called inner face defined by an inner periphery surface, and a casing 8 covering the said electric thermo element (s) 7 comprising at least one so-called first slot intake 9 and a second slot called exhaust 10 hot exhaust gas. Note that the outer and inner faces of the electric thermo elements 7 are for example circular. However, more generally, any section of rounded shape, such as an oval shape for example, and / or polygonal is possible. Such elements operate, according to the Seebeck effect, by making it possible to create an electric current in a load connected between the inner and outer faces of the electric thermo elements 7n, 7p subjected to temperature gradient. In a manner known to those skilled in the art, such elements consist, for example, of Bismuth and Tellurium (Bi ₂ Te ₃ ).

The electric thermoelectric elements 7 may be, for a first part, elements 7p of a first type, called P, making it possible to establish an electric potential difference in a direction, called positive, when they are subjected to a gradient of given temperature, and, for the other part, elements 7n of a second type, called N, allowing the creation of a difference of electric potential in an opposite direction, called negative, when they are subjected to the same gradient of temperature.

In Figures 1 and 2, the electric thermo elements 7 shown consist of a ring in one piece. They may however be formed of several pieces each forming an angular portion of the ring.

The outer surface has, for example, a radius of between 1.5 and 4 times the radius of the inner surface. It could be a radius equal to about 2 times that of the inner surface.

Said thermoelectric element 7 has, for example, two opposite parallel flat faces. In other words, the ring constituting the thermoelectric element 7 is of rectangular annular section. Said thermoelectric elements 7p, 7n are arranged, for example, in the longitudinal extension of one another, in particular in a coaxial manner, and the P-type thermoelectric elements alternate with the N-type thermoelectric elements, according to a direction D. They are, in particular, of identical shape and size. They may, however, have a thickness, that is to say a dimension between their two planar faces, different from one type to another, particularly depending on their electrical conductivity. Said thermoelectric elements 7p, 7n are, for example, grouped in pairs, each pair being formed of a said P-type thermoelectric element and a said N-type thermoelectric element, and the said module is configured to allow a current flow between the first surfaces of the electric thermo elements 7 of the same pair and a flow of current between the second surfaces of each of the electric thermo elements 7 of the same pair and the thermoelectric element 7 adjacent to the neighboring pair. In this way, a series flow of the electric current is ensured between the electric thermo elements 7p, 7n disposed next to each other along the direction D.

For the circulation of the heat transfer fluid of the cooling circuit, the module according to the invention comprises a cold liquid circulation channel in contact with said second surface of said electric thermo elements 7p, 7n. Said channel consists of a so-called central tube 11.

According to the above, the central tube 11 cold liquid circulation is unique and placed in the center of the module. According to one variant, a plurality of cold liquid circulation channels may be provided.

The at least one liquid circulation tube 11 is, for example, of circular section.

In FIGS. 1 and 2, it can be seen that the said module 2 comprises a cold liquid circulation tube 11 on which a plurality of electric thermoelectric elements 7 of the same type, alternating in the direction of longitudinal extension D of the tube 11, are mounted with a electric thermo element of the other type. The tubes 11 are, in particular, metallic. They define at least in part said channel. Said module 2 may furthermore comprise electrical insulation means, not shown in the figures, arranged between two faces vis-à-vis neighboring thermoelectric elements 7p, 7n in the direction of longitudinal extension D of the tube 11 .

Said module 2 further comprises first electrical connection means 12 connecting the outer periphery surfaces of two of said thermoelectric elements 7, provided adjacent and of different types. Said first electrical connection means 12 include, for example, a layer of electrically conductive material, especially copper and / or nickel, coating said electric thermo elements 7p, 7n.

Said module 2 advantageously comprises secondary exchange surfaces, in particular fins 13, with the exhaust gases. This increases the exchange surface between the electric thermo elements 7 and said exhaust gases. Said fins 13 are arranged, for example, transversely, in particular radially to said electric thermo elements 7. They are here positioned parallel to each other with a spacing allowing a good heat exchange with the exhaust gas while limiting the losses of loads. Said fins 13 may be off-center with respect to said electric thermo elements 7p, 7n, in particular elongated on the side of the arrival of the second fluid.

Said fins 13 may comprise a catalytic coating for catalytic conversion of toxic components of the second fluid. In the case of exhaust gas, said module 2 can in this way equip a catalytic converter in addition or substitution of components conventionally used for catalysis in such equipment. Said fins 13 are fixed, for example, on said first electrical connection means 12, in particular by crimping and / or brazing.

The module 2 may also include second electrical connection means 14 establishing an electrical connection between the inner periphery surfaces of two of said adjacent thermoelectric elements 7, of different types and not connected by said first electrical connection means 12. Otherwise said, said first 12 and second 14 electrical connection means connect two said electric thermo elements in pairs so as to establish an electrical circulation in series between said thermoelectric elements 7 of the module 2. Furthermore, the envelope 8 covering the elements Electric thermo 7 may be in one piece or in two assembled parts 8a, 8b.

According to the embodiment shown in FIG. 1, said envelope 8 consists of two parts 8a, 8b respectively corresponding to a fraction of tube of circular cross section, each fraction of tube being substantially hemi-cylindrical, and closed at its ends respectively by a washer 15 of complementary shape, that is to say of circular shape, comprising at least two lugs extending outwardly from the periphery of said washer 15 so as to form at least two slots 9 and 10 between said fractions of tubes 8a, 8b.

Advantageously, the inner wall of the casing 8 is supported on the fins 13. Thus, the entire flow of exhaust gas flows through the fins 13 of the electric thermo elements 7.

Moreover, the parts 8a, 8b of the envelope 8, as well as the washers 15, are obtained in a material having dielectric properties to ensure the electrical insulation of the electric thermo elements 7 with the external environment. In addition, said portions 8a, 8b of the envelope 8 and the washers 15 are obtained in a material having a temperature withstand of at least 800 ° C. Thus, preferably, the portions 8a, 8b of the casing 8 and the washers 15 are obtained in molded ceramic, extruded mica or alumina.

Advantageously, the intake and exhaust slots 10 are arranged in such a way that the passage section given by the slots 9 and 10 is equivalent to the passage section through the fins 13.

With reference to FIG. 1, said exhaust gas intake manifold 4 consists of a cylindrical nozzle 16 opening into the casing 3 while flaring out and the collector 5 of the heat transfer fluid of the cooling circuit consists of a coupling hydraulic and electric.

Said hydraulic and electrical connection, with reference to FIGS. 1, 3 and 4, consists of a cylindrical crown-shaped housing whose body 17 comprises two side walls 18, 19 which have the shape of a disk provided with a circular central hole 20, a cylindrical inner wall 21 and a cylindrical outer wall 22, holes 23 formed on one of the side walls 19 for receiving the central tubes 11 of the thermoelectric modules 2, said holes 23 being provided with means for 24 in this embodiment, said holes 23 receiving the central tubes 11 of the electric thermo modules 2 are uniformly distributed around the central hole 20 and have the number of 10. The number of holes 23 and their distribution can be easily adapted depending on the use of the thermoelectric device.

The body 17 of the coupling is obtained in a dielectric material such as a dielectric plastic, said dielectric plastic consisting of preferably in polyamide or polypropylene to provide electrical insulation of the modules 2.

Moreover, said body 17 comprises electrical contact supports 25 integral with said body 17 in order to electrically connect the thermoelectric modules 2 in series and / or in parallel. These electrical contact supports 25 consist of threaded rods 26 obtained from a material radially extending from the outer peripheral wall 22 of the housing 16. In addition, the threaded rods 26 are secured to the body 17 of the hydraulic coupling by overmoulding, gluing, or screwing said threaded rods 26 into threaded holes in said body 17.

Moreover, said body 17 comprises at least one internal partition defining at least one so-called inlet chamber and an exhaust chamber, not shown in the figures, and at least one intake manifold 27 opening into the chamber intake and a so-called exhaust pipe 28 opening into the exhaust chamber. The intake manifolds 27 and exhaust pipes 28 extend radially from the outer peripheral wall 22 of the body 17. The holes 23 receiving the tubes 11 of the electric thermo modules 2 open into the intake chambers and the exhaust chambers in order to put in fluid communication the output of the central tube 11 of a first thermoelectric module 2 with the input of a central tube 11 of a second thermoelectric module 2.

Referring to Figures 1 and 5, the exhaust manifold 6 has a conical shape in communication with gutters 29 extending between two modules 2 of adjacent electrical thermo elements 7 respectively comprising an inlet slot 30 in fluid communication with the escape slot 10 of a module 2. With reference to FIGS. 1 and 5, the hot exhaust gases are introduced into the casing 3 via the intake manifold 4 at the center of the modules 2 of electric thermoelectric elements and then is introduced into the envelopes 8 of said modules 2 via the intake slots 9 of said envelopes 8. The exhaust gases pass through all the fins 13 before emerging envelopes 8 via the exhaust slots 10 and to be recovered by the gutters 29 and The heat transfer fluid of the cooling circuit is introduced into the intake manifold 4 via the intake manifolds 27 so that it circulates in the central tubes 11 via the exhaust manifold 6. the hydraulic connection of the exhaust manifold 6 before escaping through the exhaust pipes 28 of the hydraulic coupling of the intake manifold 4. Said exhaust manifold 6 also comprises a hydraulic connection and electric consisting of an inner ring having holes receiving the central tubes 11 of the electric thermo modules 2 in which circulates the heat transfer fluid of the cooling circuit, said ring having internal walls, not shown in the figures, to put in communication two tubes Thus, this second hydraulic and electrical connection is constituted, in the same manner as above, a cylindrical ring-shaped housing whose body 17 comprises two side walls 18, 19 which have the shape of a disc provided with a circular central hole 20, a cylindrical inner wall 21 and a cylindrical outer wall 22, holes 23 made on one of the side walls 19 for receiving the central tubes 11 of the thermoelectric modules 2, said holes 23 being provided with sealing means 24 consisting of O-rings positioned in said holes 23. The body 17 is obtained from a dielectric material such as a dielectric plastic, said dielectric plastic preferably consisting of polyamide or polypropylene to provide electrical insulation modules 2. Furthermore, said body 17 also comprises electrical contacts 25 secured to said body 17 to electrically connect in series and / or in parallel the thermoelectric modules 2. These electrical contact supports 25 consist of threaded rods 26 obtained in a plastic material and extending radially from the peripheral wall In addition, the threaded rods 26 are secured to the body 17 forming the hydraulic coupling by overmolding, gluing, or screwing said threaded rods 26 into tapped holes in said body 17. Said body 17 also comprises at least one internal partition defining at least one so-called admission chamber and a so-called exhaust chamber, not shown in the figures, the holes 23 receiving the tubes 11 of the electric thermo modules 2 opening into the intake chambers and the chambers exhaust system in order to put in fluid communication the outlet of the central tube 11 of a first thermal module o electric 2 with the input of a central tube 11 of a second thermoelectric module 2.

Thus, this second hydraulic and electrical connection is identical to the first hydraulic connection with the exception of intake and exhaust pipes. Note that said connectors combine the electrical and hydraulic functions thus reducing the size of the components providing these functions and reduce costs by providing a single piece for these two functions. In this respect, the two connections being identical with the exception of intake and exhaust pipes, the same mold can be used for their manufacture thus reducing production costs.

Thus, with reference to FIG. 5, the hydraulic and electrical connection of the intake manifold 4 receives the inlet of the central tube 11 of a first thermoelectric module 2 at the level of the intake chamber into which the tubing of the admission 27 and the output of the central tube 11 of a second thermoelectric module 2 at the exhaust chamber into which the exhaust manifold 28 opens. The electrical input of the first electrical module is connected to a first threaded rod 26 of the hydraulic and electrical connection of the intake manifold 4 and the electrical output is connected to a second threaded rod 26 of the hydraulic and electrical connection of the intake manifold 4 Furthermore, the hydraulic and electrical connection of the exhaust manifold 6 receives the output of the central tube 11 of the first thermoelectric module 2 at the level of the exhaust chamber and the inlet of the central tube 11 of the second thermoelectric module 2 at the level of the admission chamber. The intake and exhaust chambers of the hydraulic coupling of the exhaust manifold 6 being in fluid communication, the two electric thermo modules 2 are hydraulically connected in series. Moreover, the electrical output of the first electrical module 2 and the electrical input of the second electric thermo module 2 are connected to a threaded rod 26 of the hydraulic and electrical connection of the exhaust manifold 6 so that the two electric thermo modules 2 are electrically connected in series. Said connections thus make it possible to electrically and hydraulically connect two electric thermo modules 2 in series.

Note that in this embodiment, the various electric thermo modules are electrically mounted in series but any other electrical scheme may be considered.

It is understood that the present invention is in no way limited to the embodiments described above and that modifications can be made without departing from the scope of the appended claims.

Claims

1. Hydraulic coupling for a thermoelectric device comprising a plurality of electric thermo modules (2), each thermoelectric module (2) comprising at least a plurality of cylindrical thermoelectric elements (7p, 7n) comprising a central circular recess receiving a tube central (11), said electric thermo elements (7p, 7n) being capable of generating an electric current under the action of a temperature gradient exerted between a first so-called outer face defined by an outer periphery surface and a so-called second surface face interior defined by an inner periphery surface, a first fluid being adapted to flow through the central tube (11) and a second fluid being adapted to circulate around the outer periphery, said connector comprising a body (17) provided with means for placing in fluid communication the outlet of the central tube (11) of a first thermoelectric module (2) with the input of a central tube (11) of a second thermoelectric module (2) and at least one support for electrical contacts (24) integral with said body (17).

2. Hydraulic coupling according to claim 1 wherein the body (17) is obtained in a dielectric material.

3. Hydraulic coupling according to claim 2 wherein the body (17) is obtained in a dielectric plastic.

The hydraulic coupling of claim 3 wherein the dielectric plastic consists of polyamide or polypropylene.

5. Hydraulic coupling according to any one of claims 1 to 4 wherein the one or more electrical contact carriers (24) consist of threaded rods (25) obtained in a plastic material.

6. Hydraulic coupling according to claim 5 wherein the threaded rods (25) are secured to the body (17) of the hydraulic coupling by overmolding.

7. Hydraulic coupling according to claim 5 wherein the threaded rods (25) are secured to the body (17) of the hydraulic connection by gluing.

8. A hydraulic coupling according to claim 5 wherein the threaded rods (25) are secured to the body (17) of the hydraulic coupling by screwing said rods into threaded holes in said body (17).

9. Hydraulic coupling according to any one of claims 1 to 8 wherein the body (17) consists of a cylindrical crown-shaped housing, having two side walls (18,19) which have the shape of a disc provided with a circular central hole (20), a cylindrical inner wall (21) and a cylindrical outer wall (22), holes (23) on one (19) of the side walls (18, 19) for receiving the central tubes (11) of the thermoelectric modules (2), said holes (23) being provided with sealing means (24), at least one internal partition defining at least one so-called inlet chamber and a so-called chamber exhaust, and at least one intake manifold (27) opening into the intake chamber and an exhaust pipe (28) opening into the exhaust chamber.

10. Hydraulic coupling according to claim 9 wherein the intake manifolds (27) and exhaust (28) extend radially from the outer peripheral wall (22) of the body (17).

11. A hydraulic coupling according to claims 5 to 10 wherein the threaded rods (26) extend radially from the outer peripheral wall (22) of the body (17).

12. Hydraulic coupling according to any one of claims 9 to 11 wherein the sealing means (24) consist of O-rings positioned in the holes (23) receiving the central tubes (11).

13. Hydraulic coupling according to any one of claims 9 to 12 wherein the holes (23) receiving the central tubes are uniformly distributed around the body (17).

14. Thermoelectric device comprising at least a plurality of electric thermo modules (2), each thermoelectric module (2) comprising at least a plurality of cylindrical thermoelectric elements (7p, 7n) comprising a central circular recess receiving a central tube (11), said electric thermo elements (7p, 7n) being capable of generating an electric current under the action of a temperature gradient exerted between a first so-called outer face defined by an outer periphery surface and a second inner so-called face defined by an inner periphery surface, a first fluid being intended to flow through the central tube (11) and a second fluid being intended to circulate around the outer periphery, and at least one hydraulic coupling according to any one of the claims 1 to 13 above for placing in fluid communication the outlet of the central tube (11) of a first module electric thermo (2) with the entry of a central tube (11) of a second thermoelectric module (2).

15. A thermoelectric device according to claim 14 configured to be positioned in a motor vehicle exhaust gas duct, said gases defining the second fluid.