FR3081980A1 - DEVICE FOR HEAT TREATMENT OF AN ELECTRICAL ENERGY STORAGE ELEMENT AND METHOD FOR MANUFACTURING SUCH A DEVICE - Google Patents

Abstract

The invention relates to a device for heat treatment of an electrical energy storage element. The heat treatment device comprises at least one manifold and a plurality of tubes (2) capable of channeling a heat transfer fluid. At least one tube (2) is delimited at least by an internal face (14) intended to come into contact with the heat transfer fluid and by an external face (15) intended to be thermally coupled to the electric energy storage element. The manifold comprises at least one manifold plate, a cover and a seal disposed between the tube (2) and the manifold plate. The external face (15) of the tube (2) is covered at least partially with a dielectric element (19).

Description

Device for heat treatment of an electrical energy storage element and method for manufacturing such a device

The present invention relates to devices for heat treatment of an electrical energy storage element. It relates to such a heat treatment device. It also relates to a method of manufacturing such a heat treatment device.

The electric energy of vehicles with electric and / or hybrid motorization is supplied by an electric energy storage element comprising one or more batteries. One problem is that during operation, the batteries heat up and risk being damaged. It is therefore necessary to use a heat treatment device in order to maintain the batteries at an acceptable temperature.

Such a heat treatment device, also called a heat exchanger, comprises a bundle of tubes connecting together at least two manifolds in which are connected, in a fixed and sealed manner, corresponding ends of the tubes. A heat transfer fluid can then flow through the tubes and the manifolds in order to thermally exchange with the batteries, which are in particular in direct or indirect contact with the tubes. Each of the manifolds into which the tubes of the bundle open includes a manifold plate having orifices for passage of the tubes.

The constituent elements of the heat treatment device are for example assembled together mechanically, in other words by interlocking and / or by establishing a mechanical connection. Such a mechanical assembly is, for example, crimping, tightening, strapping or the like, excluding any brazing operation. We can for example refer to document W02018 / 020140 which describes such a heat treatment device.

It is desirable to electrically isolate the heat treatment device from its external environment and in particular from the electrical energy storage element comprising the battery or batteries, without however compromising an optimal desired heat exchange between the heat treatment device and The batteries. It is known to connect the heat treatment device to the mass of the motor vehicle, in particular by means of an electrically conductive wire associated with a support flange, but the connection between the heat treatment device, the wire, the flange and the mass is likely to be defective or broken.

A problem posed in the field therefore lies in the search for a better compromise to be found between on the one hand an optimized heat exchange between the heat treatment device and the electrical energy storage element and on the other hand a simple, inexpensive, space-saving, reliable and long-lasting electrical insulation between the heat treatment device and the electrical energy storage element.

An object of the present invention is to provide a heat treatment device which responds to the above problem and a method of manufacturing such a heat treatment device which is simple, quick to implement and inexpensive.

A device of the present invention is a heat treatment device, also called a heat exchanger, for an element for storing electrical energy. The heat treatment device comprises at least one manifold and a plurality of tubes capable of channeling a heat transfer fluid. At least one tube is delimited at least by an internal face intended to come into contact with the heat-transfer fluid and by an external face intended to be thermally coupled to the electric energy storage element. The manifold comprises at least one manifold, a cover and a seal between the manifold and the tubes on the one hand, and between the manifold and said cover on the other hand.

By joint is meant an attached sealing device, that is to say which is distinct from the other components of the manifold. Advantageously, the manifold comprises a single sealing device in which are formed as many holes as the heat exchanger comprises tubes. If the heat exchanger according to the invention comprises two manifolds at the two ends of the tubes, then another sealing device is also arranged between each tube and the passage orifice through which the second end of the tube concerned opens into the manifold. Similarly, the other sealing device then comprises a plurality of through holes, each intended to receive the second end of one of the tubes. The joint can advantageously seal between the tubes and the collector plate, and the collector plate and the cover.

According to the present invention, the external face of the tube is covered at least partially with a dielectric element.

The heat treatment device advantageously comprises any one of at least the following technical characteristics, taken alone or in combination:

- The heat treatment device can include a single manifold or two manifolds between which the tubes are interposed. The manifolds and tubes, and the components of the manifold, are assembled together mechanically. Such a mechanical assembly is for example crimping, tightening, strapping or the like, excluding any soldering operation,

- the external face comprises a flat surface for receiving the electrical energy storage element,

the internal face of the tube at least partially defines a path for circulation of the heat transfer fluid,

- the tube may comprise a circulation channel for the heat transfer fluid or several circulation channels for the heat transfer fluid separated from each other by means of at least one partition wall,

the electric energy storage element comprises at least one electric battery designed to supply electric energy to an electric motor fitted to the motor vehicle,

- the manifold is free of dielectric element, the latter covering only the outer face of the tube,

- the dielectric element is a polymer,

the polymer comprises any one of the polymers chosen from a list of polymers comprising polyaurolactam, polypropylene and polyetheretherketone.

- the chosen polymer can optionally be loaded with a ceramic, this ceramic filler having the advantage of being a good thermal conductor and a good electrical insulator, which satisfies the desired compromise,

- the dielectric element is an anodized compound placed on the external face of the tube,

- the tube and the dielectric element are coextruded,

- the tube comprises at least one flat surface for receiving the electrical energy storage element,

- The tube has a rectangular or oblong cross section which includes at least the flat surface for receiving the electric energy storage element. The flat surface is the part of the tube that comes into contact with the electrical energy storage element,

- the tube extends longitudinally between a first end and a second end, the dielectric element extends longitudinally at least partially, or even completely, between a first border and a second border, and the joint extends longitudinally between a line internal contact with the tube and an external contact line with the tube,

- The cover and the collector plate defines a circulation chamber for the heat transfer fluid. The tube has an end portion which is housed inside the heat transfer fluid circulation chamber. The tube has an outer part which is interposed between the manifolds, the outer part being interposed between the two end parts of a tube in question. A joint separates each end part of the tube from the external part of the same tube. In other words, by traversing a tube from its first end to its second end, there is successively a first end portion housed inside a first manifold, then a first joint which extends between a first line of internal contact and a first external contact line, then the external part interposed between the first manifold and a second manifold, then a second seal which extends between a second external contact line and a second internal contact line, then a second end part housed inside the second manifold,

the dielectric element extends longitudinally between the first edge and the second edge, either continuously or discontinuously, regardless of all or part of the external face, regardless of all or part of a peripheral periphery of the external face, the first border and the second border being the longitudinal ends of the dielectric element which are the most distant from each other,

- the external face of at least the external part of the tube is covered with the dielectric element,

- The first border is interposed between the first end of the tube and the first line of internal contact of the joint with the tube, it is understood throughout the description of the present invention by interposition of an element between two terminals of a interval the fact that the element considered is likely to be superimposed with one or the other of the two limits of the interval,

- according to a variant, the first border is superimposed with the first end of the tube,

according to another variant, the first border is superimposed with the first line of internal contact of the seal with the tube,

the first border is interposed between the first external contact line of the first seal with the tube and the second external contact line of the second seal with the tube,

- according to a variant, the first border is superimposed with the first external contact line of the first joint with the tube,

the second border is interposed between the second end of the tube and the second interior contact line of the second seal with the tube,

- according to a variant, the second border is superimposed with the second end of the tube,

according to another variant, the second border is superimposed with the second interior contact line of the second seal with the tube,

the second border is interposed between the first external contact line of the first seal with the tube and the second external contact line of the second seal with the tube,

according to another variant, the second border is superimposed with the second external contact line of the second seal with the tube,

- According to a variant, the external face of the external part of the tube and the external face of the internal part of the tube are covered with the dielectric element.

The present invention also relates to a method of manufacturing a thermal treatment device, such as that described above, of an electrical energy storage element. The heat treatment device comprises at least one manifold and a plurality of tubes capable of channeling a heat transfer fluid. At least one tube is delimited at least by an internal face intended to come into contact with the heat-transfer fluid and by an external face intended to be thermally coupled to the electric energy storage element. The manifold includes at least one manifold, a cover, and a seal disposed between the tube and the manifold. The manufacturing process includes a step of supplying a dielectric element on the external face of the tube before a step of assembling the tubes and the manifold.

The step of assembling the tubes and the manifold, and of the manifold as such, comprises at least one mechanical assembly phase, for example by interlocking and / or crimping, in particular for the manifold, tubes and the manifold and does not have a brazing phase to achieve this mechanical connection. Note that a brazing step is possible in the manufacturing process of the heat treatment device before or after the step of assembling the tubes and the manifold.

The manufacturing process advantageously comprises at least any one of the following technical characteristics, taken alone or in combination:

- the step of adding the dielectric element to the external face of the tube is a step of applying a paint comprising the dielectric element to the external face of the tube.

- the step of supplying the dielectric element to the external face of the tube is a catalytic deposition step of the dielectric element in which the external surface of the tube forms an anode.

- the step of adding the dielectric element to the external face of the tube is a step of coextruding the tube and the dielectric element around the tube.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below by way of indication in relation to the drawings in which:

- Figure 1 is a perspective view of a heat treatment device according to the invention,

FIG. 2 is a diagrammatic illustration of a cross section of a tube participating in the heat treatment device illustrated in FIG. 1,

FIG. 3 is a sectional view of a collecting box constituting the heat treatment device illustrated in FIG. 1,

FIG. 4 is a partial view of the heat treatment device illustrated in FIG. 1, according to a first alternative embodiment,

- Figure 5 is a partial view of the heat treatment device illustrated in Figure 1, according to a second alternative embodiment.

It should first be noted that the figures show the invention in detail to implement the invention, said figures can of course be used to better define the invention if necessary.

In the figures, the elements of the present invention are represented inside an orthonormal reference frame Oxyz, which comprises a longitudinal axis Ox, a lateral axis Oy and a vertical axis Oz. A longitudinal element extends along an axis parallel to the longitudinal axis Ox, a lateral element extends along an axis parallel to the lateral axis Oy, a vertical element extends along an axis parallel to the vertical axis Oz . A longitudinal plane is parallel to the Oxz plane, a transverse plane is parallel to the Oyz plane and a horizontal plane is parallel to the Oxy plane.

In Figure 1 is illustrated a perspective view of a heat treatment device 1 according to an embodiment of the present invention. The heat treatment device 1, also called a heat exchanger, is intended to equip a motor vehicle of the hybrid or electric type to cool an electric energy storage element which comprises one or more batteries forming an energy source for the motor vehicle drive.

The heat treatment device 1 comprises a bundle of tubes, or conduits, 2 rectilinear and of the same length which are placed parallel to each other and aligned parallel to the longitudinal axis Ox, so as to form a single row in which a liquid coolant, such as glycol water or the like, is intended to circulate.

In this embodiment, the tubes 2 have a straight cross section of substantially oblong shape, as illustrated in FIG. 2. The tubes 2 are for example made of extruded aluminum and are capable of comprising a plurality of juxtaposed channels for circulation heat transfer liquid.

Each tube 2 extends longitudinally between a first end 3 and a second end 4. As shown in FIG. 1, the first end 3 of each tube 2 is intended to be assembled with a first manifold 5 and the second end 4 of each tube 2 is intended to be assembled with a second manifold 6.

The first manifold 5 comprises a first manifold plate 7 and a first cover 8 which are associated together to delimit a first chamber 9 for circulation of the heat transfer fluid. The first ends 3 of the tubes 2 open out inside the first chamber 9.

The second manifold 6 includes a second manifold plate 10 and a second cover 11 which are associated together to delimit a second chamber 12 for circulation of the heat transfer fluid. The second ends 4 of the tubes 2 open out inside the second chamber 12.

According to the illustrated variant, the first manifold 5 is provided with an inlet 13a of the heat transfer fluid inside the heat treatment device 1 and an outlet 13b of the heat transfer fluid outside the heat treatment device 1. In this case there, the first manifold 5 houses a partition which separates the heat transfer fluid entering inside the first manifold 5 and the heat transfer fluid exiting from the first manifold 5. Other methods of arrival and evacuation of the heat transfer fluid is possible without departing from the rules of the present invention.

In Figure 2, a cross section is illustrated formed along a plane parallel to the Oyz plane. The tube 2 is delimited by an internal face 14 intended to come into contact with the heat transfer fluid and by an external face 15 intended to be thermally coupled to the electric energy storage element. The internal face 14 is the face of the tube 2 which at least partially borders the circulation channels 16 of the heat transfer fluid inside the tube 2. Two contiguous circulation channels 16 are separated from each other by a wall 17 According to another embodiment, the tube 2 houses a single channel for circulation of the heat transfer fluid. The external face 15 is the face of the tube which is oriented towards an external environment of the tube 2. The external face 15 is the visible face of the tube 2 by an observer looking at the tube from the external environment to the latter. The external face 15 is the face of the tube 2 which gives the latter its overall geometric shape.

According to the illustrated embodiment, the tube 2 has a cross section of oblong shape. The external face 15 comprises at least one planar surface 18, and preferably two planar surfaces 18 formed opposite one another, and on either side of the circulation channels 16. At least the one of the flat surfaces 18 is capable of forming a support for the element for storing electrical energy.

To electrically insulate the heat treatment device 1 and the electrical energy storage element, the external face 15 of the tube 2 is at least partially covered with a dielectric element 19. The dielectric element 19 forms an envelope of the tube 2 and is capable of completely covering the external face 2 in at least one transverse plane of the tube 2, as illustrated in FIG. 2. The dielectric element 19 is arranged in a layer of a first thickness El taken between the external face 15 of the tube 2 and an outer surface 20 of the dielectric element layer 19 which is less than a second thickness E2 of the tube 2 taken between the external face 15 and the internal face 14 of the tube 2. As an indication, the first thickness El is commonly between 0.07 mm and 0.35 mm. Such a small thickness makes it possible in particular not to reduce the cooling capacity of the heat treatment device 1 compared to a heat treatment device 1 free of a layer of dielectric element.

According to an alternative embodiment, the dielectric element 19 is a polymer, such as polyaurolactam, polypropylene, polyetheretherketone, the chosen polymer possibly or not being able to be charged with a ceramic. In the case of polyaurolactam, the first thickness El of the dielectric element is for example of the order of 0.225 mm to within +/- 25%. In the case of homopolymer polypropylene, the first thickness El of the dielectric element is for example of the order of 0.082 mm to within +/- 25%. In the case of copolymer polypropylene, the first thickness El of the dielectric element is for example of the order of 0.090 mm to within +/- 25%. In the case of polyetheretherketone, the first thickness El of the dielectric element is for example of the order of 0.238 mm to within +/- 25%. In the case of polyetheretherketone loaded with a ceramic, the first thickness El of the dielectric element is for example of the order of 0.079 mm to within +/- 25%. This case is particularly advantageous in the sense that ceramic is a good thermal conductor and a good electrical insulator. These thicknesses are measured, for each polymer, at a voltage of 4.5kV.

According to another variant, the dielectric element 19 is a compound placed by anodization on the external face 15 of the tube 2.

According to another variant, the tube 2, in particular made of aluminum, and the dielectric element layer 19 are obtained jointly by extrusion.

In FIG. 3, the manifold 5, 6, indifferently first manifold 5 or second manifold 6, houses a seal 21 which is interposed between the manifold plate 7, 10 and the tube 2. The seal is in particular made of a material elastomer, ethylene-propylene-diene monomer in particular. The seal 21 comprises a ply 23 which is provided with two peripheral beads 22 interposed between the cover 8, 11 and the collector plate 7, 10. The ply 23 is also provided with orifices 24 formed in a central zone of the ply 23 for the passage of the ends 3, 4 of the tubes 2 through it. The orifices 24 are of a conformation identical to the conformation of the tubes 2, namely oblong in the example illustrated. The orifices 24 extend into collars 25, commonly known as teats, for retaining the manifold 5,6. The collars 25 extend perpendicular to the ply 23. The collars 25 also have a shape complementary to the shape of the tubes 2 intended to pass through them. A lip 26 formed on each collar 25 retains the seal 21 on the manifold 5, 6 and thus prevents the seal 21 from falling from the manifold 5, 6.

The ends 3, 4 of the tubes 2 have flares 27 to immobilize in position the assembly formed by the cover 8, 11, the collecting plate 7, 10, the seal 21 to prevent this assembly from sliding along the tubes 2. By elsewhere, the collector plate 7, 10 has at its periphery retaining claws 28 in position of the cover 8, 11 and of the collector plate 7, 10. These arrangements are part of a mechanical assembly between them of the constituent elements of the treatment device thermal 1, excluding any step of soldering them of these elements.

Such an arrangement of the constituent elements of the heat treatment device 1 can be shown diagrammatically as in FIG. 4. The tube 2 extends longitudinally between the first end 3 of the tube 2 and the second end 4 of the tube 2, the first end 3 of tube 2 being housed inside the first manifold 5 and the second end 4 of tube 2 being housed inside the second manifold

6. It follows that the tube 2 comprises a first end portion 29 housed inside the first manifold 5, an outer portion 30 which is interposed between the manifolds and a second end portion 31 which is housed at inside the second manifold 6.

The seal 21 extends longitudinally between an interior contact line 32 with the tube 2 and an exterior contact line 33 with the tube 2. The interior contact line 32 is housed inside the manifold 5, 6 while that the external contact line 33 is interposed between the manifolds 5, 6. In other words, by traversing the tube 2 from the first end 3 of the tube 2 to the second end 4 of the tube 2, the first part is encountered successively terminal 29 housed inside the first manifold 5, then a first seal 21 which extends between a first internal contact line 32 and a first external contact line 33, then the external part 30 of the tube 2 interposed between the first manifold 5 and a second manifold 6, then a second seal 21 which extends between a second external contact line 33 and a second contact line inner side 32, then the second end portion 31 housed inside the second manifold 6.

The dielectric element 19 extends longitudinally between a first border 34 and a second border 35.

In FIG. 4, the first border 34 is superimposed on the first end 3, and the second border 35 is superimposed on the second end 4. In other words, the entire external surface 15 is covered with the dielectric element 19.

In FIG. 5, the first border 34 is superimposed on the first external contact line 33 of the first seal 21, and the second border 35 is superimposed on the second external line 33 of the second seal 21. In other words, only the external part 30 of the tube 2 is covered with the dielectric element 19.

Such a heat treatment device 1 is obtained from a manufacturing process which comprises a step of supplying the dielectric element 19 to the external face 15 of the tube 2 before a step of assembling the tubes 2 and the manifold 5, 6.

According to a first variant, the step of adding the dielectric element 19 to the outer face 15 of the tube 2 is a step of applying a paint comprising the dielectric element 19 to the outer face 15 of the tube 2.

According to a second variant, the step of supplying the dielectric element 19 to the external face 15 of the tube 2 is a step of catalytic deposition of the dielectric element 19 in which the external surface 15 of the tube 2 forms an anode.

According to a third variant, the step of adding the dielectric element 19 to the external face 15 of the tube 2 is a step of coextruding the tube 2 and the dielectric element 19 around the tube 2.

Claims (10)

1. A heat treatment device (1) for an electrical energy storage element, the heat treatment device (1) comprising at least one manifold (5, 6) and a plurality of tubes (2) capable of channeling a heat transfer fluid, at least one tube (2) being delimited at least by an internal face (14) intended to come into contact with the heat transfer fluid and by an external face (15) intended to be thermally coupled to the storage element d electrical energy, the manifold (5, 6) comprising at least one manifold plate (7, 10), a cover (8, 11) and a seal (21) disposed between the tube (2) and the manifold plate (7 , 10), characterized in that the external face (15) of the tube (2) is covered at least partially with a dielectric element (19). 2. Heat treatment device (1) according to claim 1, characterized in that the dielectric element (19) is a polymer. 3. Heat treatment device (1) according to claim 2, characterized in that the polymer is chosen from a list of polymers comprising polyaurolactam, polypropylene, polyetheretherketone, the chosen polymer being able to be charged with a ceramic. 4. Heat treatment device (1) according to any one of the preceding claims, characterized in that the dielectric element (19) is an anodized compound placed on the external face (15) of the tube (2). 5. A heat treatment device (1) according to any one of claims 1 to 3, characterized in that the tube (2) and the dielectric element (19) are coextruded. 6. A heat treatment device (1) according to any one of the preceding claims, characterized in that the tube (2) extends longitudinally between a first end (3) and a second end (4), the dielectric element (19) extends longitudinally at least partially between a first border (34) and a second border (35), and the seal (21) extends longitudinally between an internal contact line (32) with the tube (2) and an external contact line (33) with the tube (2). 7. Heat treatment device (1) according to the preceding claim, characterized in that the first edge (34) is interposed between the first end (3) of the tube (2) and the interior contact line (32) of the seal ( 21) with the tube (2), and in that the second edge (35) is interposed between the second end (4) of the tube (2) and the second inner contact line (33) of the second seal (21) with the tube (2). 8. A heat treatment device (1) according to claim 6, characterized in that the first edge (34) is interposed between a first external contact line (33) of a first seal (21) with the tube (2) and a second external contact line (33) of a second seal (21) with the tube (2), and in that the second edge (35) is interposed between the first external contact line (33) of the first seal (21) with the tube (2) and the second external contact line (33) of the second seal (21) with the tube (2). 9. A method of manufacturing a heat treatment device (1) of an electrical energy storage element, the heat treatment device (1) comprising at least one manifold (5, 6) and a plurality of tubes (2) capable of channeling a heat transfer fluid, at least one tube (2) being delimited at least by an internal face (14) intended to come into contact with the heat transfer fluid and by an external face (15) intended to be thermally coupled to the electrical energy storage element, the manifold box (5, 6) comprising at least one manifold plate (7, 10), a cover (8, 11) and a seal (21) disposed between the tube (2) and the collector plate (7, 10), characterized in that the manufacturing method comprises a step of supplying a dielectric element (19) on the external face (15) of the tube (2) prior to a step of assembly of the tubes (2) and the manifold (5, 6). 10. Manufacturing method according to the preceding claim, characterized in that the step of supplying the dielectric element (19) on the external face (15) of the tube (2) is a step of applying a paint comprising the dielectric element (19) on the external face (15) of the tube (2).