FR3121076A1 - Cooling module for electric or hybrid motor vehicle with tangential turbomachine with power electronics cooling - Google Patents

Abstract

Cooling module (22) for an electric or hybrid motor vehicle (10), said cooling module (22) being intended to be crossed by a flow of air (F) and comprising:- a fairing (40) forming an internal channel through which the air flow (F) passes between an upstream end (40a) and a downstream end (40b) opposite to each other, said fairing (40) comprising at least one heat exchanger (24, 26, 28), - a first collector box (41) disposed downstream of the fairing (40) in a longitudinal direction (X) of the cooling module (22) extending from the front to the rear of said cooling module (22), - a second collector box (42) arranged upstream of the fairing (40) opposite the first collector box (41), the cooling module (22) comprising on the external face of one of its walls a specific unit of cooling (29) of a power electronics device (292) of the motor vehicle, said specific cooling unit (29) comprising fins (290) passing through the wall of the cooling module (22) and projecting inside said cooling module (22). Abstract Figure: Fig 4

Description

Cooling module for electric or hybrid motor vehicle with tangential turbomachine with power electronics cooling

The present invention relates to a cooling module for an electric or hybrid motor vehicle, with a tangential turbomachine.

A cooling module (or heat exchange module) of a motor vehicle conventionally comprises at least one heat exchanger and a ventilation device adapted to generate an air flow in contact with the at least one heat exchanger. The ventilation device thus makes it possible, for example, to generate a flow of air in contact with the heat exchanger, when the vehicle is stationary or at low driving speed.

In motor vehicles with a conventional heat engine, the at least one heat exchanger is substantially square in shape, the ventilation device then being a propeller fan whose diameter is substantially equal to the side of the square formed by the heat exchanger.

Conventionally, the heat exchanger is then placed opposite at least two cooling bays, formed in the front face of the motor vehicle body. A first cooling bay is located above the bumper while a second bay is located below the bumper. Such a configuration is preferred because the heat engine must also be supplied with air, the air intake of the engine being conventionally located in the passage of the air flow passing through the upper cooling bay.

However, electric vehicles are preferably provided only with cooling bays located under the bumper, more preferably with a single cooling bay located under the bumper. Indeed, the electric motor does not need to be supplied with air. In addition, the reduction in the number of cooling bays improves the aerodynamic characteristics of the electric vehicle. This also translates into better autonomy and a higher top speed of the motor vehicle.

However, this means that the space available for arranging the cooling module is reduced and that the latter must be smaller in size. The space devoted to the heat exchangers is therefore limited and consequently their number and their exchange surface are also limited. This thus leads to a limitation of the general heat exchange capacity at the level of the cooling module which can be detrimental for the cooling of all the necessary elements, in particular within an electric or hybrid vehicle.

The object of the present invention is therefore to at least partially remedy the drawbacks of the prior art and to propose an improved cooling module allowing better performance by limiting the increase in its size.

The present invention therefore relates to a cooling module for an electric or hybrid motor vehicle, said cooling module being intended to be traversed by a flow of air and comprising:
- a fairing forming an internal channel through which the air flow passes between an upstream end and a downstream end opposite to each other, said fairing comprising at least one heat exchanger,
- a first collector box disposed downstream of the fairing in a longitudinal direction of the cooling module extending from the front to the rear of said cooling module,
- a second collector box arranged upstream of the fairing opposite the first collector box,
the cooling module comprising on the outer face of one of its walls a specific unit for cooling a power electronics device of the motor vehicle,
said specific cooling unit comprising fins passing through the wall of the cooling module and protruding inside said cooling module.

According to one aspect of the invention, the specific cooling unit is arranged on the wall of the first manifold box.

According to another aspect of the invention, the specific cooling unit is arranged on a side wall of the first manifold box.

According to another aspect of the invention, the specific cooling unit is arranged on a guide wall arranged facing the downstream end of the fairing.

According to another aspect of the invention, the specific cooling unit is arranged on a wall of the second collector box.

According to another aspect of the invention, the specific cooling unit is an integral part of the wall of the cooling module.

According to another aspect of the invention, the wall of the cooling module comprises at least one through hole, the specific cooling unit being fixed to the wall so that the fins pass through the at least one through hole.

According to another aspect of the invention, the specific cooling unit is an element distinct from the power electronics device and from the wall of the cooling module.

According to another aspect of the invention, the specific cooling unit is an integral part of the power electronics device.

According to another aspect of the invention, the specific cooling unit comprises a base intended to be integral with the power electronics device, the fins protruding from said base.

According to another aspect of the invention, the specific cooling unit is made of a thermally conductive metallic material.

According to another aspect of the invention, the fins of the specific cooling unit extend towards the inside of the cooling module over a distance less than or equal to 20 mm.

According to another aspect of the invention, the fins of the specific cooling unit have a tubular shape.

Other characteristics and advantages of the present invention will appear more clearly on reading the following description, provided by way of illustration and not limitation, and the appended drawings in which:

the shows a schematic representation of the front of a motor vehicle in side view,

the shows a schematic representation in perspective and in partial section of the front of a motor vehicle and a cooling module,

the shows a schematic sectional representation of a cooling module,

the shows a schematic representation in perspective of a first manifold housing of a cooling module according to a first embodiment,

the shows a schematic representation in perspective of a specific cooling unit according to a first embodiment,

the shows a schematic representation in perspective of a specific cooling unit according to a second embodiment,

the shows a schematic representation in perspective of a specific cooling unit according to a third embodiment,

the shows a schematic representation in perspective of a specific cooling unit according to a fourth embodiment.

In the various figures, identical elements bear the same reference numbers.

The following achievements are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference is to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments may also be combined and/or interchanged to provide other embodiments.

In the present description, it is possible to index certain elements or parameters, such as for example first element or second element as well as first parameter and second parameter or else first criterion and second criterion, etc. In this case, it is a simple indexing to differentiate and name elements or parameters or criteria that are close, but not identical. This indexing does not imply a priority of one element, parameter or criterion over another and such denominations can easily be interchanged without departing from the scope of the present description. Nor does this indexing imply an order in time, for example, to assess such and such a criterion.

In the present description, the term "upstream" means that one element is placed before another with respect to the direction of circulation of an air flow. On the contrary, by “downstream” we mean that one element is placed after another in relation to the direction of circulation of a flow or a fluid.

In figures 1 to 4, an XYZ trihedron is represented in order to define the orientation of the various elements from each other. A first direction, denoted X, corresponds to a longitudinal direction of the vehicle. It also corresponds to the reverse of the direction of travel of the vehicle. A second direction, denoted Y, is a lateral or transverse direction. Finally, a third direction, denoted Z, is vertical. The directions, X, Y, Z are orthogonal two by two.

In Figures 1 and 2, the cooling module according to the present invention is illustrated in a functional position, that is to say when it is arranged within a motor vehicle.

The schematically illustrates the front part of an electric or hybrid motor vehicle 10 which may include an electric motor 12. The vehicle 10 comprises in particular a body 14 and a bumper 16 carried by a chassis (not shown) of the motor vehicle 10. The body 14 defines a cooling bay 18, that is to say an opening through the body 14. The cooling bay 18 is unique here. This cooling bay 18 is preferably located in the lower part of the front face 14a of the bodywork 14. In the example illustrated, the cooling bay 18 is located under the bumper 16. A grille 20 can be arranged in the cooling bay 18 to prevent projectiles from passing through the cooling bay 18. A cooling module 22 is arranged opposite the cooling bay 18. The grid 20 makes it possible in particular to protect this cooling module 22.

As shown in , the cooling module 22 is intended to be traversed by an air flow F parallel to the direction X and going from the front to the rear of the vehicle 10. This direction X corresponds more particularly to a longitudinal direction X going from the front to the rear of the cooling module 22. In the present application, an element is qualified as "upstream" or "downstream" according to the longitudinal direction X of the cooling module 22, an element which is respectively arranged further forward or backward than another element. The front corresponds to the front of the motor vehicle 10 in the assembled state or else the face of the cooling module 22 through which the air flow F is intended to enter the cooling module 22. to him at the rear of the motor vehicle 10 or else to the face of the cooling module 22 through which the air flow F is intended to come out of the cooling module 22.

The cooling module 22 essentially comprises a casing or shroud 40 forming an internal channel between an upstream end 40a and a downstream end 40b opposite each other. Inside said fairing 40 is arranged at least one heat exchanger 24, 26, 28. This internal channel is preferably oriented parallel to the longitudinal direction X so that the upstream end 40a is oriented towards the front of the vehicle. 10 opposite the cooling bay 18 and so that the downstream end 40b is oriented towards the rear of the vehicle 10. On the the cooling module 22 comprises three heat exchangers 24, 26, 28 grouped together within a set of heat exchangers 23. It could however comprise more or less depending on the desired configuration.

A first heat exchanger 24 can for example be configured to release heat energy from the air flow F. This first heat exchanger 24 can more particularly be a condenser connected to a cooling circuit (not shown), for example in order to cool the batteries of the vehicle 10. This cooling circuit can for example be an air conditioning circuit able to cool the batteries as well as an internal air flow intended for the passenger compartment of the motor vehicle.

A second heat exchanger 26 can also be configured to release heat energy into the air flow F. This second heat exchanger 26 can more particularly be a radiator connected to a thermal management circuit (not shown) for example of the electric motor 12.

The first heat exchanger 24 generally being a condenser of an air conditioning circuit, the latter needs the air flow F to be as "cool" as possible in air conditioning mode. For this, the second heat exchanger 26 is preferably arranged downstream of the first heat exchanger 24 in the longitudinal direction X of the cooling module 22. It is nevertheless quite possible to imagine that the second heat exchanger 26 is arranged upstream of the first heat exchanger 24.

The third heat exchanger 28 can also be configured to release heat energy into the airflow. This third heat exchanger 28 may more particularly be a radiator connected to a thermal management circuit (not shown), which may be separate from that connected to the second heat exchanger 26, for electrical elements such as power electronics. It is also quite possible to imagine that the second 26 and the third 28 heat exchanger are connected to the same thermal management circuit, for example connected in parallel with each other.

Still according to the example illustrated in , the second heat exchanger 26 is arranged downstream of the first heat exchanger 24 while the third heat exchanger 28 is arranged upstream of the first heat exchanger 24. Other configurations can nevertheless be envisaged, such as for example the second 26 and third 28 heat exchangers both arranged downstream or upstream of the first heat exchanger 24.

In the illustrated embodiment, each of the heat exchangers 24, 26, 28 has a generally parallelepipedal shape determined by a length, a thickness and a height. The length extends along the Y direction, the thickness along the X direction and the height in the Z direction. vertical Z and the lateral direction Y. This general plane is preferably perpendicular to the longitudinal direction X of the cooling module 22.

Still as shown in , the cooling module 22 also comprises a first manifold box 41 disposed downstream of the set of heat exchangers 23 in the direction of circulation of the air flow. This first collector box 41 comprises an outlet 45 for the air flow F, This first collector box 41 thus makes it possible to recover the flow of air F passing through the set of heat exchangers 23 and to direct this air flow F to the outlet 45. The first manifold housing 41 can be made in one piece with the fairing 40 or else be an added part fixed to the downstream end 40b of said fairing 40. This first manifold housing 41 is also shown in more detail in FIGS. 3 and 4.

The cooling module 22, more precisely the first collector box 41, also comprises at least one tangential fan, also called tangential turbomachine 30, configured so as to generate the air flow F passing through the set of heat exchangers 23. The tangential turbomachine 30 comprises a rotor or turbine 32 (or tangential propeller). The turbine 32 has a substantially cylindrical shape. The turbine 32 advantageously comprises several stages of blades (or blades), visible on the . The turbine 32 is rotatably mounted around an axis of rotation A, for example parallel to the direction Y as shown in the . The diameter of the turbine 32 is for example between 35 mm and 200 mm to limit its size. The turbomachine 30 is thus compact.

The tangential turbomachine 30 can also comprise a motor 31 (visible on the ) configured to rotate the turbine 32. The motor 31 is for example adapted to drive the turbine 32 in rotation, at a speed between 200 rpm and 14,000 rpm. This makes it possible in particular to limit the noise generated by the tangential turbomachine 30.

The tangential turbomachine 30 is arranged in the first collector box 41. The tangential turbomachine 30 is configured to suck in air in order to generate the air flow F passing through the set of heat exchangers 23. The tangential turbomachine 30 comprises more specifically a volute 44, formed by the first manifold housing 41 and at the center of which is arranged the turbine 32. The air discharge from the volute 44 corresponds to the outlet 45 of the air flow F from the first manifold housing 41 .

In the example illustrated in FIGS. 2 to 4, the tangential turbomachine 30 is in a high position, in particular in the upper third of the first manifold housing 41, preferably in the upper quarter of the first manifold housing 41. This makes it possible in particular to protect the tangential turbomachine 30 in the event of submersion and/or to limit the size of the cooling module 22 in its lower part.

It is nevertheless possible to imagine that the tangential turbomachine 30 is in a low position, in particular in the lower third of the first manifold housing 41. This would limit the size of the cooling module 22 in its upper part. Alternatively, the tangential turbomachine 30 can be in a middle position, in particular in the middle third of the height of the first manifold box 41, for example for reasons of integration of the cooling module 22 in its environment.

By upper and lower is meant here an orientation in the direction Z. A so-called upper element will be closer to the roof of the vehicle 10 and a so-called lower element will be closer to the ground.

In order to guide the air leaving the set of heat exchangers 23 towards the outlet 45, the first collector box 41 comprises, arranged facing the downstream end 40b of the fairing 40, a guide wall 46 of the flow of air F towards the outlet 45. This guide wall 46 makes more particularly the junction with an upstream edge 451 of the outlet 45 of the air flow F. By upstream edge 451, we mean here the edge of the outlet 45 the closer to the downstream end 40b of the fairing 40.

The guide wall 46 forms an angle α with a first plane P1 perpendicular to the longitudinal direction X of the cooling module 22. This angle α is more particularly between 0° and a maximum angle of 25°, preferably 23°. If the angle α is 0° then the guide wall 46 coincides with the perpendicular P1 to the longitudinal direction X of the cooling module 22. The maximum angle of 25° corresponds to the angle α' d 'a second plane of maximum inclination P2 (visible on the ) with the foreground P1. Preferably, the guide wall 46 is inclined and the angle α is between 5 and 25° with respect to the first plane P1.

This second plane of maximum inclination P2 connects more precisely the upstream edge 451 of the outlet 45 and a downstream end edge 230 of the at least one heat exchanger 24, 26, 28. By downstream end edge 230, here is meant the edge of a heat exchanger 24, 26, 28 closest to the downstream end 40b of the fairing 40. When the fairing 40 comprises several heat exchangers 24, 26, 28, the downstream end edge 230 taken into consideration is the downstream end edge 230 of the most downstream heat exchanger, here the second heat exchanger 26. The downstream end edge 230 is arranged opposite the outlet 45 of the heat flow. air f.

The fact that the guide wall 46 forms an angle α comprised between 0° and 25° and more particularly when it is inclined at an angle α comprised between 0° and 25° allows better circulation of the flow of air F within of the first manifold box 41 and limits the loss of charges.

As illustrated on the , the cooling module 22 may also include a second manifold housing 42 disposed upstream of the shroud 40 and of the set of heat exchangers 23, opposite the first manifold housing 41. This second manifold housing 42 comprises an inlet 42a of the flow of air F coming from outside the vehicle 10. The inlet 42a can in particular be arranged facing the cooling bay 18. This inlet 42a can also include the protective grid 20 . The second collector box 42 can be made in one piece with the fairing 40 or else be an attached part fixed to the upstream end 40a of said fairing 40.

In addition, the inlet 42a of the second collector box 42 may comprise a front face shutter device (not shown) movable between a first so-called open position and a second so-called closed position. This front face closing device is configured in particular to allow the air flow F coming from outside the vehicle 10 to pass through said inlet 42a in its open position and to close said air flow inlet 42a in its closed position.

The front face closure device can be in different forms, such as for example in the form of a plurality of flaps mounted to pivot between an open position and a closed position. The flaps can in particular be mounted parallel to the Y direction. However, it is entirely possible to imagine other configurations such as, for example, flaps mounted parallel to the Z direction. Other types of shutters such as butterfly shutters are quite possible.

Always according to , the cooling module 22 comprises, on the outer face of one of its walls, a specific unit 29 for cooling a power electronics device 292 (visible in FIGS. 5 to 8) of the motor vehicle. By external surface of one of the walls of the cooling module 22, is meant more precisely the surface oriented towards the outside of the cooling module 22. The power electronics device 292 can in particular be one or more of the following elements :
- a converter from direct current to alternating current for the electric motor 12,
- a current voltage regulator from the batteries to a lower voltage, for example 24V or 12V; or
- an on-board battery charger.

The specific cooling unit 29 comprises fins 290 (visible in FIGS. 3 and 4) passing through the wall of the cooling module 22 and projecting inside said cooling module 22. Through the interior of the cooling module 22 more particularly means the internal zone of the cooling module 22 in which the flow of air F is intended to circulate. Thus, the fins 290 are brought into contact with the air flow F passing through the cooling module 22. By being in contact with the air flow F, the fins 290 make it possible to dissipate the heat produced by the electronic device power 292. The latter is thus passively cooled by the air flow F. The fact of placing the specific cooling unit 29 directly on the external face of a wall of the cooling module 22 also makes it possible to use an area “dead”, not used, within the cooling module 22. The use of a cooling circuit dedicated to cooling the power electronics is thus not necessary. Such a dedicated cooling circuit would have taken up space in an already limited space. In addition, such a circuit would have increased the weight of the cooling module 22 by adding a heat exchanger within the fairing 40 as well as of the motor vehicle by adding the various components such as a pump and the pipes. . In addition, the fact that the cooling is done here passively, no electrical energy is used, unlike a dedicated circuit whose pump must be electrically powered. Finally, such a specific cooling unit 29 allows savings in the manufacturing cost of the cooling module 22.

As illustrated in FIGS. 2 to 4, the specific cooling unit 29 can be arranged more precisely on a wall of the first collector box 41. The fact of arranging the specific cooling unit 29 on the first collector box 41 makes it possible not to not increase the size of the cooling module 22. In fact, the location of the cooling element 29 is here an unused zone of the first manifold housing 41 between the downstream end 40b of the shroud 40 and the volute 44.

According to a first embodiment illustrated in FIGS. 2 to 4, the specific cooling unit 29 can in particular be arranged on a side wall of the first manifold box 41. According to a second embodiment (not shown) the specific cooling unit 29 can be arranged on the guide wall 46. This second embodiment is possible in particular when said guide wall 46 does not include relief flaps (not shown) configured to open under the pressure of the air flow F when driving the motor vehicle above a determined speed.

According to a variant not shown, the specific cooling unit 29 can be placed on a wall of the second manifold box 42. Another variant not shown can also be that the specific cooling unit 29 is placed on the external face of the fairing 40 The fins 290 then protrude upstream, downstream or between the heat exchangers 24, 26, 28.

The fins 290 of the specific cooling unit 29 preferably have a tubular shape. This particular shape of the fins is particularly suitable when the specific cooling unit 29 is arranged on a side wall of the first manifold box 41. Indeed, here, the air flow F can have different orientations depending on the conditions and this tubular shape fins 290 makes it possible to limit pressure drops. For example, when driving the motor vehicle above a determined speed, the air flow F can be rectilinear along the axis X and pass through the load shedding flaps (not shown) configured to s' open under the pressure of the air flow F. On the contrary, as shown in the , when the vehicle is stopped or at low speed, when the turbine 32 is in operation, the air flow F goes up the guide wall 46 to pass through the volute 44.

It is of course quite possible to imagine other shapes for the fins 290, for example a shape of slats parallel to each other and parallel to the axis of the orientation of the air flow F. This is particularly useful to increase the exchange surface by limiting the increase in pressure drops, in particular in areas where the air flow has a constant orientation, for example at the level of the second manifold box 42 or of the fairing 40.

Still in order to limit the pressure drops of the air flow F within the cooling module 22, the fins 290 of the specific cooling unit 29 can extend towards the inside of the cooling module 22 over a shorter distance or equal to 20mm.

In order to improve thermal conduction and therefore allow good cooling of the power electronics device 292, the specific cooling unit 29 can advantageously be made of a thermally conductive metallic material such as copper and/or aluminum for example.

Figures 5 to 8 show in more detail the specific cooling unit 29 according to different embodiments.

As illustrated in FIGS. 5 to 8, the specific cooling unit 29 may in particular comprise a base 291 intended to be integral with the power electronics device 292. The fins 290 protrude from said base 291 on a face opposite that in contact with the power electronics device 292. The fins 290 and the base 291 can be made in one piece, for example by machining or molding, or else each fin 290 can be an added part and fixed on the base 291.

According to a first embodiment illustrated in , the specific cooling unit 29 can be an integral part of the wall of the cooling module 22. According to this first embodiment, the power electronics device 292 can be fixed on the specific cooling unit 29 which forms an integral part of the wall of the cooling module 22. The specific cooling unit 29 can in particular be molded onto the wall of the cooling module 22. According to this first embodiment, the base 291 can thus form an integral part of the wall of the cooling module 22.

According to a second embodiment illustrated in at 8, the wall of the cooling module 22 may comprise at least one through hole 220. The specific cooling unit 29, more precisely its base 291, is then fixed to the wall so that the fins 290 pass through the at least one least one through hole 220.

The shows a first variant of the second embodiment in which the wall of the cooling module 22 comprises a single through orifice 220 through which all the fins 290 pass. FIGS. 7 and 8 show a second variant of the second embodiment embodiment in which the wall of the cooling module 22 comprises a multitude of through-holes 220. In the context of this second variant, each fin 290 has a dedicated through-hole 220.

According to a first example of this second embodiment illustrated in FIGS. 6 and 7, the specific cooling unit 29 can be a separate element from the power electronics device 292 and from the wall of the cooling module 22. The cooling device power electronics 292 and the specific cooling unit 29 can be fixed to each other and the power electronics device 292 with its specific cooling unit 29 is then fixed to the external face of the wall of the cooling module 22 so that the fins 290 pass through the at least one through hole 220. Alternatively, the specific cooling unit 29 can be fixed first to the wall of the cooling module 22 and then the device of power electronics 292 is fixed on the wall of the cooling module 22 so as to be in contact with the specific cooling unit 29 or else directly on the unit specific cooling 29, more precisely on the face opposite the fins 290 of the base 291.

According to a second example of the second embodiment illustrated by the , the specific cooling unit 29 can be an integral part of the power electronics device 292. For example, the specific cooling unit 29 and in particular its fins 290, can be constituent elements of a box comprising within electronic elements. According to this second example, the base 291 then forms an integral part of the casing of the power electronics device 292.

Thus, it is clear that the cooling module 22 due to the presence of the specific cooling unit 29 allows thermal regulation of a power electronics device 292 directly by means of fins 290 arranged in the flow of air F without having recourse to a cooling circuit taking up space, being heavy and increasing manufacturing costs.

Claims (10)

Cooling module (22) for an electric or hybrid motor vehicle (10), said cooling module (22) being intended to be crossed by a flow of air (F) and comprising:
- a fairing (40) forming an internal channel through which the air flow (F) passes between an upstream end (40a) and a downstream end (40b) opposite to each other, said fairing (40) comprising at at least one heat exchanger (24, 26, 28),
- a first collector box (41) disposed downstream of the fairing (40) in a longitudinal direction (X) of the cooling module (22) extending from the front to the rear of said cooling module (22),
- a second manifold housing (42) arranged upstream of the fairing (40) opposite the first manifold housing (41),
characterized in that the cooling module (22) comprises on the outer face of one of its walls a specific unit (29) for cooling a power electronics device (292) of the motor vehicle,
said specific cooling unit (29) comprising fins (290) passing through the wall of the cooling module (22) and protruding inside said cooling module (22). Cooling module (22) according to the preceding claim, characterized in that the specific cooling unit (29) is arranged on a wall of the first collector box (41). Cooling module (22) according to Claim 2, characterized in that the specific cooling unit (29) is arranged on a side wall of the first collector box (41). Cooling module (22) according to Claim 2, characterized in that the specific cooling unit (29) is arranged on a guide wall (46) arranged facing the downstream end (40b) of the fairing (40) . Cooling module (22) according to Claim 1, characterized in that the specific cooling unit (29) is arranged on a wall of the second collector box (42). Cooling module (22) according to any one of Claims 1 to 5, characterized in that the specific cooling unit (29) forms an integral part of the wall of the cooling module (22). Cooling module (22) according to any one of Claims 1 to 5, characterized in that the wall of the cooling module (22) comprises at least one through orifice (220), the specific cooling unit (29) being attached to the wall so that the fins (290) pass through the at least one through hole (220). Cooling module (22) according to Claim 7, characterized in that the specific cooling unit (29) is a separate element from the power electronics device (292) and from the wall of the cooling module (22). Cooling module (22) according to Claim 7, characterized in that the specific cooling unit (29) forms an integral part of the power electronics device (292). Cooling module (22) according to any one of the preceding claims, characterized in that the specific cooling unit (29) comprises a base (291) intended to be integral with the power electronics device (292), the fins (290) protruding from said base (291).