THERMAL MANAGEMENT SYSTEM FOR AN ELECTRIC COMPONENT

Abstract

A thermal management system for an electric component has a housing for the electric component and a heat exchange plate extending over the surface of the lateral face of the housing. The plate has a fluid channel between a fluid inlet and a fluid outlet, a supply duct to supply the plate with fluid and a discharge duct, a casing defining the housing(s) and receiving the heat exchange plate and the supply and discharge ducts. The system includes a fluid collecting box arranged to collect fluid from a possible fluid leakage at the junction between the fluid inlet and the fluid outlet of the plate and the associated supply and discharge ducts, so as to prevent said leaked fluid from dripping into a bottom of the casing.

Claims

1. A thermal management system for at least one electrical component, comprising: at least one housing intended to receive the at least one electrical component; at least one heat-exchange plate extending over at least part of a surface of a lateral face of the at least one housing, said at least one heat-exchange plate including a fluid inlet, a fluid outlet and at least one heat-transfer fluid canal for a heat-transfer fluid between the fluid inlet and the fluid outlet; an intake duct configured to supply the heat-exchange plate with the heat-transfer fluid via the fluid inlet of the at least one heat-exchange plate and a discharge duct configured to remove the heat-transfer fluid from the at least one heat-exchange plate via the fluid outlet thereof; a casing defining the at least one housing and receiving the at least one heat-exchange plate and the intake and discharge ducts; a fluid collecting tank arranged to collect any fluid that might leak from junction between the fluid inlet and the fluid outlet of the at least one heat-exchange plate and the associated intake duct and discharge duct, so as to prevent this leaking fluid from dropping into the casing.

2. The system as claimed in claim 1, wherein the system includes a plurality of heat-exchange plates, with junctions between the intake duct, the discharge duct and the fluid inlet and the fluid outlet for each heat-exchange plate, and wherein the fluid collecting tank is common to all the heat-exchange plates so as to collect any fluid that might be leaking from all of the junctions associated with all of the heat-exchange plates.

3. The system as claimed in claim 2, wherein the collecting tank extends perpendicular to the heat-exchange plates.

4. The system as claimed in claim 1, wherein the at least one heat-exchange plate includes a connecting part which has the fluid inlet and the fluid outlet, the connecting part extending over just part of one side of the associated at least one heat-exchange plate.

5. The system as claimed in claim 4, wherein the fluid collecting tank comprises a notch receiving the connecting part of the at least one heat-exchange plate.

6. The system as claimed in claim 5, wherein there is sealing between the notch of the fluid collecting tank and the connecting part of the at least one heat-exchange plate.

7. The system as claimed in claim 1, wherein the collecting tank has a bottom and lateral walls.

8. The system as claimed in claim 1, wherein the collecting tank contains a plastics material and is formed as a single piece.

9. The system as claimed in claim 1, wherein the system includes at least one sensor designed to detect presence of water in the fluid collecting tank.

10. A battery pack including a thermal management system for at least one electrical component, having: at least one housing intended to receive the at least one electrical component; at least one heat-exchange plate extending over at least part of a surface of a lateral face of the at least one housing, said at least one heat-exchange plate including a fluid inlet, a fluid outlet and at least one heat-transfer fluid canal for a heat-transfer fluid between the fluid inlet and the fluid outlet; an intake duct configured to supply the heat-exchange plate with the heat-transfer fluid via the fluid inlet of the at least one heat-exchange plate and a discharge duct configured to remove the heat-transfer fluid from the at least one heat-exchange plate via the fluid outlet thereof; a casing defining the at least one housing and receiving the at least one heat-exchange plate and the intake and discharge ducts; a fluid collecting tank arranged to collect any fluid that might leak from a junction between the fluid inlet and the fluid outlet of the at least one heat-exchange plate and the associated intake duct and discharge duct, so as to prevent this leaking fluid from dropping into the casing; said battery pack including the at least one electrical component in form of an electrical energy storage module received in the at least one housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Other features, details and advantages of the invention will become apparent upon reading the detailed description below, and upon analyzing the appended drawings, in which:

[0060] FIG. 1 schematically depicts a perspective view of a battery pack equipped with a cooling device according to one embodiment of the invention;

[0061] FIG. 2 schematically depicts a perspective view of part of the cooling device of FIG. 1 without the electrical energy storage modules;

[0062] FIG. 3 schematically depicts the direction of circulation of the heat-transfer fluid in a plate of FIG. 2;

[0063] FIG. 4 schematically depicts an exploded view of a plate of heat-transfer fluid canals of FIG. 3;

[0064] FIG. 5 depicts an enlarged perspective view of a region of communication between the first series of canals and the second series of canals, viewed from the side of the first series of canals;

[0065] FIG. 6 depicts an enlarged perspective view of a region of communication between the first series of canals and the second series of canals, viewed from the side of the second series of canals;

[0066] FIG. 7 depicts an enlarged perspective view of a supply region of the canals of the plate;

[0067] FIG. 8 depicts an enlarged perspective view of a discharge region of the canals of the plate;

[0068] FIG. 9 depicts an enlarged view of the fluid inlet and outlet of a plate, the inlet and the outlet being equipped with tubular connection endpieces;

[0069] FIG. 10 depicts an enlarged view of a region of connection between two plates by pipes, one of the two plates being an end plate of a row;

[0070] FIG. 11 depicts another exemplary implementation of the invention;

[0071] FIG. 12 depicts a view of FIG. 11 with the collecting tank;

[0072] FIG. 13 depicts the collecting tank of the system of FIG. 12; and

[0073] FIG. 14 depicts another exemplary implementation of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0074] The drawings and the description below contain, for the most part, elements of a certain character. Therefore, they not only can be used to better understand the present invention, but they also contribute to its definition, if applicable.

[0075] A first embodiment of a thermal management system for an electrical component 101 liable to release heat when operating is illustrated in FIG. 1 and FIG. 2.

[0076] An electrical component 101 is, for example, a rechargeable electrical energy storage device such as an electric battery or a battery module or an individual electrical cell.

[0077] FIG. 1 illustrates an example of an electrical component 101 in form of an electric module which has a substantially parallelepipedal shape comprising a base and lateral walls.

[0078] In FIG. 1, the modules are distributed in form of lines of modules, notably lines of two modules, to form a battery pack 100. Each module comprises a plurality of individual cells. Each cell is contained in a wrapper which is made of a thermally conducting material such as aluminum. Thus, each module comprises a horizontal heat-exchange surface and lateral heat-exchange surfaces. When the battery is operating, the cells heat up and it is therefore necessary to cool these cells or the module in order to keep the cells at an optimal operating temperature. Furthermore, it is appropriate to cool all of the cells uniformly.

[0079] According to the example illustrated in FIG. 1, the thermal management system comprises a plurality of housings 2 delimited by a bottom face 5, two longitudinal lateral faces 3 and a plurality of transverse lateral faces 4. Each housing 2 is configured to accept one or more electrical modules, in this instance arranged in a line of two modules.

[0080] Each module has a long side and a short side. Thus, in each line, the long sides of the aligned modules form two transverse lateral heat-exchange surfaces.

[0081] The thermal management system comprises a plurality of heat-exchange plates 10, each of the heat-exchange plates 10 extending over at least part of the transverse lateral surface to form a vertical surface for contact with the vertical heat-exchange surface formed by the long sides of a line of modules. The heat-exchange plate 10 comprises heat-transfer fluid canals 14 through which a heat-transfer fluid circulates in order to cool the line of modules through exchange of heat.

[0082] The heat-transfer fluid used is preferably glycol-water, with no limit on the glycol content (0% to 100%). Alternatively, the heat-transfer fluid can be chosen from among designated refrigerants.

[0083] In FIG. 1, the transverse lateral faces 4, the bottom 5 and the longitudinal lateral faces 3 form seven housings 2, each housing 2 being configured to receive a line of two modules. The thermal management system comprises eight heat-exchange plates 10 (here referenced to as 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8) arranged parallel to one another to form a row of heat-exchange plates 10. Thus, each transverse lateral face 4 of each line of modules is cooled by a heat-exchange plate 10. As can be seen in FIG. 1, the end heat-exchange plates 10 of the row or the peripheral heat-exchange plates 10 (here referenced to as 10.1, 10.8) are in contact with a transverse lateral face 4 of the line of modules.

[0084] Preferably, the heat-exchange plate 10 extends entirely over the transverse lateral face 4 of the line of modules.

[0085] As can be seen in FIG. 3, the heat-exchange plate 10 comprises a plurality of heat-transfer fluid canals 14 intended to cool the modules. The heat-transfer fluid canals 14 are parallel to one another and extend over substantially the entire length of the heat-exchange plate 10.

[0086] A border of each heat-exchange plate 10 comprises a fluid inlet 22 and a fluid outlet 23.

[0087] Preferably, when all the heat-exchange plates 10 are aligned to form a row of heat-exchange plates 10, all the fluid inlets 22 and all the fluid outlets 23 are aligned along an axis X′X as illustrated in FIG. 2.

[0088] In order to ensure uniform cooling across all the modules or cells to reduce the temperature discrepancy between the cells, the heat-transfer fluid canals 14 are arranged in such a way that the direction in which fluid circulates alternates in a vertical direction between the fluid inlet 22 and the fluid outlet 23 of the heat-exchange plate 10.

[0089] The thermal management system comprises an intake duct 30 configured to supply each of the heat-exchange plates 10 with fluid in parallel, and a discharge duct 31 configured to jointly collect the fluid at the fluid outlet 23 of each of the heat-exchange plates 10.

[0090] The intake duct 30 is connected to the fluid inlets 22 of the heat-exchange plates 10 in order to supply the heat-exchange plates 10 in parallel, and the discharge duct 31 is connected to the fluid outlets 23 of the heat-exchange plates 10 in order to collect in parallel the fluid coming from the heat-exchange plates 10. Furthermore, the intake duct 30 and the discharge duct 31 respectively comprise a main inlet 32 and a main outlet 33 which are intended to be connected to a fluid circuit external to the cooling device.

[0091] In order to maintain an identical flowrate of the heat-transfer fluid through all the heat-exchange plates 10, the main inlet 32 and the main outlet 33 are positioned with respect to the fluid inlets 22 and the fluid outlets 23 of each of the heat-exchange plates 10 in such a way that the length of the path covered by the heat-transfer fluid from the main inlet 32 to the main outlet 33 is the same for each of the heat-exchange plates 10.

[0092] According to one embodiment of the invention and as illustrated in FIG. 1, the main inlet 32 is situated on one side of the battery pack 100 and the main outlet 33 on the opposite side of the battery pack 100.

[0093] In the example illustrated in FIG. 1, the main inlet 32 is situated on the fluid inlet 22 of the peripheral heat-exchange plate 10 (here referenced to as 10.1) and the outlet 33 is situated on the fluid outlet 23 of the peripheral heat-exchange plate 10 (here referenced to as 10.8). The length of the path covered by the fluid for each of the eight heat-exchange plates 10 is the same.

[0094] Preferably, the intake duct 30 and discharge duct 31 are parallel to one another and to axes X′X. They extend transversely with respect to the heat-transfer fluid canals 14 on the transverse lateral face 3.

[0095] Thus, the intake and outlet ducts 30, 31 and the end heat-exchange plates 10 at least partially form the perimeter of the battery pack 100.

[0096] The heat-exchange plate will now be described in detail with reference to FIG. 3 to FIG. 8.

[0097] As mentioned above, the heat-exchange plate 10 comprises heat-transfer fluid canals 14, which here include a first series of fluid intake canals 14A and a second series of fluid outlet canals 14B. The fluid intake canals 14A of the first series extend in a first plane and the fluid outlet canals 14B of the second series in a second plane. The two planes are distinct and are parallel to the transverse lateral face 4.

[0098] All the fluid intake and fluid outlet canals 14A, 14B are parallel to one another and extend over the entire length of the heat exchange plate 10. One end of each of the fluid intake canals 14A of the first series is in communication with the end of a neighboring fluid outlet canal 14B of the second series to form a plurality of U-shaped fluid paths.

[0099] Preferably, all canal communication regions 14E between the fluid intake and fluid outlet canals 14A, 14B are situated on the first side 17 of the heat-exchange plate 10. A first end 14C and a second end 14D of the U-shaped fluid path are situated on the second side 18 of the heat-exchange plate 10. The first end 14C and the second end 14D respectively form an inlet orifice for the fluid intake canal 14A, and an outlet orifice for the fluid outlet canal 14B.

[0100] The first end 14C of the U-shaped fluid path is in communication with an intake region 15 and the second end 14D is in communication with a discharge region 16. The intake region 15 and discharge region 16 have substantially elongate shapes and extend transversely with respect to the fluid intake and fluid outlet canals 14A, 14B. The intake and discharge regions 15, 16 are connected, respectively, to the fluid inlet 22 and fluid outlet 23.

[0101] Thus, and as can be seen in FIG. 3, the direction in which the fluid circulates in the heat-exchange plate 10 alternates in a vertical direction of the heat-exchange plate 10, in the heightwise sense of the heat-exchange plate 10. Specifically, when the heat-transfer fluid is circulating in the first series of fluid intake canals 14A, it becomes heated on contact with the heat-exchange surface of the modules. Thus, the fluid circulating in the second series of fluid outlet canals 14B is hotter than the fluid circulating in the first series of fluid intake canals 14A. In other words, circulation alternates between a cold canal and a hot canal in the heightwise direction of the heat-exchange plate 10. Because the module is formed of a plurality of cells positioned vertically, each cell, in terms of heat, experiences the cold canal and the hot canal of the heat-transfer fluid. Thus, the mean fluid temperature experienced by each cell is the same.

[0102] With reference to FIG. 4, the heat-exchange plate 10 is formed of a central sheet 12 interposed between two other lateral sheets 11, 13. The sheets 11, 12, 13 are produced as a single piece. They can be made of metal, notably of aluminum or of steel.

[0103] With reference to FIG. 5 and FIG. 6, the central sheet 12 comprises a first series of grooves 26 on first face 12.A to form the first series of fluid intake canals 14A, and a second series of grooves 27 on the second face 12.B to form the second series of fluid outlet canals 14B.

[0104] The central sheet 12 comprises openings 20 positioned at the ends of the grooves 26, 27 to create the canal communication region 14E between the fluid intake and fluid outlet canals 14A, 14B allowing the heat-transfer fluid to circulate from a fluid intake canal 14A of the first series to a fluid outlet canal 14B of the second series. The direction of circulation is shown by arrows in FIG. 5 and FIG. 6.

[0105] With reference to FIG. 7 and FIG. 8, the central sheet 12 comprises on the first face 12.A an intake region 15 in communication on the one hand with the inlet orifices of the fluid intake canals 14A and on the other hand with the fluid inlet 22. On the second face 12.B, the central sheet 12 comprises a discharge region 16 in communication on the one hand with the outlet orifices of the fluid intake canals 14B and on the other hand with the fluid outlet 23. The intake region 15 and the discharge region 16 are situated on the one same side 18 of the central sheet 12.

[0106] Preferably, the central sheet 12 is obtained as a single piece by stamping.

[0107] The three planar sheets 11, 12 and 13 have substantially the same dimensions and shapes. The lateral sheets 11, 13 are positioned one on each side of the central sheets 12 and close the grooves 26, 27 to form the fluid intake and fluid outlet canals 14A, 14B. The two sheets 11, 13 can be welded, bonded or assembled by brazing with the central sheet 12.

[0108] The connection of the intake region 15 and of the discharge region 16 of a heat-exchange plate 10 to the intake duct 30 and to the discharge duct 31 will now be described with reference to FIG. 9 and FIG. 10.

[0109] The intake duct 30 and the discharge duct 31 are formed from an assembly of a plurality of intake pipes 35 and discharge pipes 36. The ends of each intake pipe 35 and discharge pipe 36 are equipped with a tubular connection duct endpiece 37. As illustrated in FIG. 1 and FIG. 10, each of the intake pipes 35 and discharge pipes 36 is positioned between two heat-exchange plates 10. The tubular connection duct endpieces 37 are connected to the fluid inlets 22 and to the fluid outlets 23 of the two heat-exchange plates 10.

[0110] FIG. 9 illustrates a heat-exchange plate 10 intended to be positioned between two lines of modules, such as the heat-exchange plates 10 referenced to as 10.2 to 10.7 in FIG. 1. The heat-exchange plate 10 comprises a through-connection 24 at the fluid inlet 22 and a through-connection 24 at the fluid outlet 23.

[0111] At the fluid inlet 22, the through-connection 24 comprises three orifices produced respectively in the central sheet 12 (see FIG. 7 and FIG. 8) and in the lateral sheets 11, 13 at the border 18 and arranged facing one another, each of the orifices in the lateral sheets 11, 13 accepting an intake tubular connection endpiece 24.1, 24.2 which extends out from one face of the heat-exchange plate 10. One end of the intake tubular connection endpieces 24.1, 24.2 is connected to the connection endpieces 37 of an intake pipe 35 forming the intake duct 30. The two intake tubular connection endpieces 24.1, 24.2 thus form a fluidic passage between two intake pipes 35 of the intake duct 30 which are positioned one on each side of the heat-exchange plate 10 and also form a fluidic passage with the heat-exchange plate 10 feed reservoir 15.

[0112] Similarly, at the fluid outlet 23, the through-connection 24 comprises three orifices produced respectively in the central sheet 12 (see FIG. 7 and FIG. 8) and in the lateral sheets 11, 13 at the border 18 and arranged facing one another, each of the orifices accepting an outlet tubular connection endpiece 24.3, 24.4 which extends out from one face of the heat-exchange plate 10. One end of the outlet tubular connection endpieces 24.3, 24.4 is connected to the connection endpieces 37 of a pipe 36 forming the discharge duct 31, as illustrated in FIG. 10. The two outlet tubular connection endpieces 24.3, 24.4 thus form a fluidic passage between two pipes 36 of the discharge duct 31 which are positioned one on each side of the heat-exchange plate 10 and also form a fluidic passage with the plate discharge reservoir 16.

[0113] FIG. 10 illustrates a heat-exchange plate 10 positioned at the end of a row of heat-exchange plates 10, referenced to as 10.1 in FIG. 1, and a neighboring heat exchange plate 10 referenced to as 10.2. This end heat exchange plate 10 comprises a through-connection 24 and a connection 25 which does not pass all the way through. In the illustrated example of FIG. 10, the through-connection 24 forms the fluid inlet 22 of the end heat-exchange plate 10 and the connection 25 that does not pass all the way through forms the fluid outlet 23 of the end heat-exchange plate 10.

[0114] Similarly, the end heat exchange plate 10 referenced as 10.8 in FIG. 1 also comprises a through-connection 24 and a connection 25 that does not pass all the way through, the through-connection 24 forming the fluid outlet 23 of the end heat-exchange plate 10 and the connection 25 that does not pass all the way through forming the fluid inlet 22 of the end heat-exchange plate 10.

[0115] In the example illustrated in FIG. 10, the through-connection 24 of the end heat-exchange plate 10 referenced to as 10.1 comprises three orifices produced respectively in the central sheet 12 (see FIG. 7 and FIG. 8) and in the lateral sheets 11, 13 at the border 18 and arranged facing one another, each of the orifices in the lateral sheets 11, 13 accepting an intake tubular connection endpiece 24.1, 24.2 which extends out from one face of the end heat-exchange plate 10. One of the intake tubular connection endpieces 24.1 forms the main inlet 32 of the thermal management system and is connected to an external fluid circuit (not illustrated). The other connection endpiece 24.2 is connected to a connection endpiece 37 of an intake pipe 35 forming the intake duct 30 which is connected to the fluid inlet 22 of the next heat-exchange plate 10; in this instance in FIG. 10 this is the heat-exchange plate 10 referenced to as 10.2. The two connection endpieces 24.1, 24.2 thus form a fluidic passage connected to the feed reservoir 15 of the end heat-exchange plate 10.1.

[0116] The heat-exchange plates 10 positioned at the center of the battery pack are in contact with the modules positioned on each side of these heat-exchange plates 10. The end heat-exchange plates 10 are in contact only with the modules positioned on one side of these heat-exchange plates 10. Thus, the end heat-exchange plates 10 will exchange a thermal power that is a factor of two lower compared with the other heat-exchange plates 10. In order to ensure the most uniform possible temperature between the cells, it is appropriate for the modules in contact with the end heat-exchange plates 10 not to be cooled excessively. In order to do that, it is necessary to increase the pressure drops experienced by the fluid at these end heat-exchange plates 10 and thus reduce the flowrate of the heat-transfer fluid. More specifically, the flowrate of the heat-transfer fluid in the end heat-exchange plates 10 referenced to as 10.1, 10.8 needs to be halved.

[0117] To do that, the present invention proposes adjusting the bore section at the connection 25 that does not pass all the way through the end heat-exchange plate 10 in order to reduce the flowrate of the heat-transfer fluid. This connection 25 that does not pass all the way through is situated on the fluid outlet 23 of the end heat-exchange plate 10.1 or on the fluid inlet 22 of the end heat-exchange plates 10 references to as 10.8.

[0118] FIG. 11 shows another exemplary embodiment of the invention.

[0119] The thermal management system 200 of FIG. 11 comprises a plurality of housings 2 as described above, and heat-exchange plate 210 extending over the surface of the lateral face of each housing 2.

[0120] Each heat-exchange plate 210 comprises one or more heat-transfer fluid canals between a fluid inlet 211 and a fluid outlet 212 of said heat-exchange plate 210, like those described in the preceding examples.

[0121] An intake duct 30 configured to supply the heat-exchange plate 210 with heat-transfer fluid via the fluid inlet 211 of the heat-exchange plate 210 and a discharge duct 31 configured to discharge the heat-transfer fluid from the heat-exchange plate 210 via the fluid outlet 212 of the heat-exchange plate 210 are provided, in the manner of the preceding examples, and these are not depicted in FIG. 11.

[0122] A casing 300 defining the housings 2 and receiving the heat-exchange plates 210 and the intake and discharge ducts 30, 31 is provided. This casing 300 defines a pack.

[0123] As visible in FIG. 12, the system 200 comprises a fluid collecting tank 215 arranged to collect any fluid that might leak from the junction between the fluid inlet 211 and fluid outlet 212 of the heat-exchange plates 210 and the associated intake and discharge ducts 30 and 31, so as to prevent this leaking fluid from dropping into a bottom of the casing 300 that forms the battery pack.

[0124] The heat-exchange plates 210 are arranged parallel to one another with, for each heat-exchange plate 210, junctions between the fluid intake and discharge ducts 30 and 31 and the plate fluid inlet 211 and fluid outlet 212, and the fluid collecting tank 215 is common to all the heat-exchange plates 210 so as to collect any fluid that might be leaking from all of the junctions associated with all of the heat-exchange plates 210.

[0125] The connecting tank 215 extends perpendicular to the heat-exchange plates 210, notably at one end 216 thereof.

[0126] Each heat-exchange plate 210 comprises a connecting part 217 which comprises the fluid inlet 211 and the fluid outlet 212, this connecting part 217 extending over just part of one side of the associated heat-exchange plate 210.

[0127] This connecting part 217 takes the form of a lug projecting on one side 218 of the heat-exchange plate 210, projecting on a side of the heat-exchange plate 210 which is the width, and this connecting part 217 is positioned in the upper part of the heat-exchange plate 210 when the heat-exchange plate 210 is in position in the system for normal use.

[0128] The fluid collecting tank 215 comprises notches 220, for receiving a connecting part 217 of one of the heat-exchange plates 210, as can be seen in FIG. 12 and FIG. 13.

[0129] There is sealing between the notch 220 of the collecting tank 215 and the connecting part 217 of the heat-exchange plate 210, for example in the form of a silicone seal.

[0130] The notches 220 have a rectilinear shape and are parallel.

[0131] The notches 220 extend over just part of the height of the collecting tank 215. In this way, the notches 220 do not extend up to the bottom of the collecting tank. The notches 220 are present only on a planar face of the tank 215.

[0132] The collecting tank 215 comprises a bottom 218 and lateral walls 219. The collecting tank 215 is open at the top.

[0133] All of the lateral walls 219 are rectangular in shape.

[0134] The collecting tank 215 contains a plastics material and is notably formed as a single piece.

[0135] The tank 215 is fixed to the housings 2, notably by bonding, screwing to the casing 300 of the pack, or else is held on the casing 300 of the pack by a clip for example.

[0136] The system 200 comprises at least one sensor 233 designed to detect the presence of water in the collecting tank 215.

[0137] This sensor 233 is a water-level sensor positioned inside the collecting tank 215. As a preference, if the collecting tank 215 is of substantial length, two sensors 233 will be positioned one at each longitudinal end of this tank 215 in order to detect a liquid leak whatever the inclination of the vehicle in the event of a leak.

[0138] As an alternative, the collecting tank 215 common to all the heat-exchange plates 210 can be replaced by a multitude of collecting tanks 215, for example each collecting tank 215 being associated with one or two heat-exchange plates 210.

[0139] As an alternative, it is possible to add several level sensors 233, at least two positioned along the vertical axis, in order to evaluate the rate of leakage in the collecting tank 215 so as to allow the vehicle to operate in a downgraded mode between initial detection of the leak and until such point as the fluid in the collecting tank 215 reaches a maximum level beyond which the vehicle is to be made safe and can no longer be used.

[0140] In an alternative illustrated in FIG. 14, an alternative collecting tank 250 is positioned along a lower edge 251 of the connecting parts. Thus, the alternative collecting tank 250 is positioned below the connecting parts 217 so that in normal operation this alternative collecting tank 250 can collect any leaking fluid that falls under gravity from the junctions of the ducts 30 and 31 to the heat-exchange plates 210.

[0141] The alternative collecting tank 250 extends from the connecting parts 217 of the heat-exchange plates 210 21 up to the foot 252 of the heat-exchange plates 210. Thus, the alternative collecting tank 250 extends over the majority of the width of the heat-exchange plates 210. In this instance, the height of the alternative collecting tank 250 runs parallel to the width of the heat-exchange plates 210.