FR3059833A1 - FUEL CELL THERMAL MANAGEMENT DEVICE AND METHOD FOR MANAGING THE SAME - Google Patents

Abstract

The present invention relates to a thermal management device (1) for a fuel cell (10), said thermal management device (1) comprising a cooling circuit (100) inside which a coolant and / or a coolant is able to circulate and comprising: ° a pump (4), ° a first heat exchanger (2) disposed at the level of the fuel cell (10), ° a second heat exchanger (3) placed in a flow of air so as to cool the coolant and / or heat transfer fluid from the first heat exchanger (2), said thermal management device (1) having a water circuit (200) resulting from the chemical reaction within the fuel cell (10), and an additional heat exchanger (5) configured to exchange heat energy between the refrigerant fluid and / or the heat transfer fluid of the cooling circuit (100) and other water from said water circuit (20 0).

Description

® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number: 3,059,833 (to be used only for reproduction orders)

©) National registration number: 16 61857

COURBEVOIE © Int Cl ⁸ : H 01 M8 / 04 (2017.01), H 01 M 8/0297

A1 PATENT APPLICATION

©) Date of filing: 02.12.16. © Applicant (s): VALEO THERMAL SYSTEMS (© Priority: Simplified joint stock company - FR. @ Inventor (s): KARL STEFAN. ©) Date of public availability of the request: 08.06.18 Bulletin 18/23. ©) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents ® Holder (s): VALEO THERMAL SYSTEMS related: Joint stock company. ©) Extension request (s): © Agent (s): VALEO THERMAL SYSTEMS.

THERMAL FUEL CELL MANAGEMENT DEVICE AND ASSOCIATED MANAGEMENT METHOD.

FR 3 059 833 - A1

The present invention relates to a thermal management device (1) for a fuel cell (10), said thermal management device (1) comprising a cooling circuit (100) inside which a coolant and / or a heat-transfer fluid. is able to circulate and comprising:

⁰ a pump (4), ⁰ a first heat exchanger (2) arranged at the fuel cell (10), ⁰ a second heat exchanger (3) placed in an air flow so as to cool the fluid refrigerant and / or heat transfer fluid from the first heat exchanger (2), said thermal management device (1) comprising a water circuit (200) resulting from the chemical reaction within the fuel cell (10) , and an additional heat exchanger (5) configured to exchange heat energy between on the one hand the refrigerant and / or the coolant of the cooling circuit (100) and on the other hand the water of said circuit d water (200).

Fuel cell thermal management device and associated management method

The invention relates to the field of thermal management within an electric vehicle. More specifically, the present invention relates to a fuel cell thermal management device.

In general, a fuel cell thermal management device comprises a cooling circuit inside which a refrigerant is able to circulate. This cooling circuit includes:

° a pump, ° a first heat exchanger placed at the level of the fuel cell, and ° a second heat exchanger placed in an air flow, generally on the front face of the vehicle, so as to cool the refrigerant coming from it the first heat exchanger,

Compared to an internal combustion engine, a fuel cell requires a more efficient cooling device for two main reasons:

• in the case of a fuel cell, almost all the heat produced must be removed by the cooling device. In fact, the quantity of heat evacuated by the products expelled from the chemical reaction in the fuel cell is low. For its part, an internal combustion engine can dissipate part of the heat produced by the large flow of exhaust gases.

• The maximum admissible operating temperature of a fuel cell is around 95 ° C while that of an internal combustion engine is around 110 ° C.

In addition, under special conditions such as uphill, the demand for power from the fuel cell is high and the vehicle speed allows only a small flow of air, insufficient to properly cool the refrigerant at the second exchanger. heat. Under these conditions, a thermal management device with a second heat exchanger having a heat exchange capacity similar to that used for an internal combustion engine is not sufficient.

In order to remedy this lack of heat exchange capacity of the second heat exchanger, several solutions are known.

It is thus possible to increase the number and / or the surface of the openings for the arrival or the evacuation of the cooling air flow. Alternatively, it is possible to increase the surface area of the second heat exchanger or to couple it with additional heat exchangers, placed for example in the wheel housings. However, these solutions induce an increase in the drag coefficient of the vehicle and limitations in the style that can be adopted by the vehicle.

Another known solution would be to use a powerful ventilation system to increase the air flow arriving at the level of the second heat exchanger. However, this solution leads to an increase in the electrical consumption, noise and weight of the vehicle and therefore also to a reduction in the range of the vehicle which is not desirable.

In addition, such solutions make it difficult for an automobile manufacturer to be able to use the same mounting platform for a model of motor vehicle which could offer various motorizations such as an electric motorization with fuel cell, an electric motorization with batteries or else an engine with an internal combustion engine.

One of the aims of the present invention is therefore to at least partially remedy the drawbacks of the prior art and to propose an improved fuel cell thermal management device.

The present invention therefore relates to a fuel cell thermal management device, said thermal management device comprising a cooling circuit inside which a refrigerant and / or a heat transfer fluid is able to circulate and comprising:

° a pump, ° a first heat exchanger placed at the level of the fuel cell, ° a second heat exchanger placed in an air flow so as to cool the coolant and / or the heat-transfer fluid coming from the first exchanger heat, said thermal management device comprising a water circuit resulting from the chemical reaction within the fuel cell, and an additional heat exchanger configured to exchange heat energy between on the one hand the refrigerant and / or the heat transfer fluid of the cooling circuit and on the other hand the water of said water circuit.

According to another aspect of the invention, the additional heat exchanger is arranged, in the cooling circuit, upstream of the second heat exchanger, between the first heat exchanger and said second heat exchanger in the direction of circulation of the refrigerant and / or heat transfer fluid.

According to another aspect of the invention, the additional heat exchanger is arranged, in the cooling circuit, downstream of the second heat exchanger, between said second heat exchanger and the first heat exchanger in the direction of circulation of the refrigerant and / or heat transfer fluid.

According to another aspect of the invention, the water circuit includes a buffer water tank resulting from the chemical reaction within the fuel cell, said buffer water tank being arranged upstream of said additional heat exchanger, in the direction of water circulation in the water circuit.

According to another aspect of the invention, the water circuit comprises, upstream of the buffer water tank, a device for controlling the water pressure, in the direction of circulation of the water in the water circuit.

According to another aspect of the invention, the water circuit comprises a compressor arranged downstream of the additional heat exchanger, in the direction of circulation of the water in the water circuit, said compressor being able to create a vacuum within said additional heat exchanger and sucking water vapor within said additional heat exchanger in order to reject it in the external environment.

According to another aspect of the invention, the compressor has a compression ratio of between 1 and 2, preferably between 1.3 and 1.7.

According to another aspect of the invention, the compressor has a compression ratio of between 1 and 3, preferably between 1.6 and 2.6, preferably between 1.9 and 2.3.

According to one aspect of the invention, the additional heat exchanger comprises:

° an enclosure in which water resulting from the chemical reaction within the fuel cell is intended to be accumulated, said enclosure comprising a water inlet pipe resulting from the chemical reaction within the fuel cell and a water vapor suction pipe disposed above the water level in the enclosure, ° at least one tube in which the coolant and / or the heat transfer fluid is able to circulate, said at least one tube being able to be immersed in water intended to be accumulated in the enclosure.

According to one aspect of the invention, the tubes in which the coolant and / or the coolant is able to circulate, are flat tubes arranged parallel to each other and connected to a coolant inlet manifold and / or heat transfer fluid at a first of their ends and a coolant outlet manifold and / or heat transfer fluid at their second end.

According to one aspect of the invention, the flat tubes have a general U shape and that the inlet and outlet manifolds of refrigerant and / or heat transfer fluid are arranged at the bottom of the enclosure.

According to one aspect of the invention, the buffer water tank is connected to the water inlet pipe of the additional heat exchanger.

According to one aspect of the invention, the compressor is connected to the water vapor suction pipe of the heat exchanger.

According to one aspect of the invention, in operation, the water level within the enclosure is maintained so that the tube or tubes remain submerged.

According to one aspect of the invention, the additional heat exchanger includes a purge device so as to be able to empty the enclosure of the water resulting from the chemical reaction within the fuel cell.

The present invention also relates to a method for managing a fuel cell thermal management device, said thermal management device comprising a cooling circuit inside which a refrigerant and / or a heat transfer fluid is able to circulate and including:

° a pump, ° a first heat exchanger placed at the level of the fuel cell, ° a second heat exchanger placed in an air flow so as to cool the coolant and / or the heat-transfer fluid coming from the first exchanger of heat, said method comprising the following steps:

° recovery of water resulting from the chemical reaction within said fuel cell, ° immersion of part of the cooling circuit in an enclosure containing recovered water so as to exchange heat energy between a the refrigerant and / or the coolant in the cooling circuit and the recovered water on the other hand.

According to one aspect of the management method according to the invention, said management method comprises an additional step of reducing the pressure within the enclosure so as to reduce the boiling temperature of the recovered water.

Other characteristics and advantages of the invention will appear more clearly on reading the following description, given by way of illustrative and nonlimiting example, and of the appended drawings among which:

FIG. 1 shows a schematic representation of a thermal management device according to a first embodiment, FIG. 2 shows a schematic representation of an additional heat exchanger of a thermal management device according to the invention, Figure 3 shows a schematic representation of a thermal management device according to a second embodiment.

Identical elements in the different figures have the same references.

The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the characteristics apply only to a single embodiment. Simple features of different embodiments can 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 even 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 similar but not identical. This indexing does not imply a priority of an element, parameter or criterion over another and one can easily interchange such names without departing from the scope of this description. This indexing does not imply an order in time for example to assess such or such criteria.

As shown in Figures 1 and 3, the thermal management device 1 of the fuel cell 10 comprises a cooling circuit 100 inside which a refrigerant is able to circulate. The cooling circuit 100 includes:

° a pump 4, ° a first heat exchanger 2 disposed at the fuel cell 10, and ° a second heat exchanger 3 placed in an air flow so as to cool the refrigerant coming from the first heat exchanger heat 2. Generally, this second heat exchanger 3 is placed on the front face of the motor vehicle.

The thermal management device 1 also comprises a water circuit 200 resulting from the chemical reaction within the fuel cell 10 and an additional heat exchanger 5 capable of exchanging heat energy between the fluid on the one hand refrigerant of the cooling circuit 100 and on the other hand the water of said water circuit 200.

This makes it possible to remove heat energy from the cooling circuit 100 and thus the second heat exchanger 3 does not need to have a high heat exchange capacity in order to be able to effectively cool the fuel cell 10. This is particularly the case in extreme conditions such as uphill, where the demand for power from the fuel cell 10 is high but where the speed of the vehicle allows only a small flow of air to cool the second heat exchanger 3. Thus, it it is possible to use a heat exchanger placed on the front panel which has a similar or similar dimension to a front panel heat exchanger used for other cooling systems of other engines, for example to cool an internal combustion engine .

This makes it possible in particular to pool the means of production of a motor vehicle and to be able to offer for the same model of vehicle different types of motorization including an electric vehicle with fuel cell, without having to modify the construction platform, see to create a new one.

In addition, this also allows greater flexibility in the style of the motor vehicle and prevents an increase in its drag coefficient by avoiding the use of a second large heat exchanger 3. It is also not necessary to add to the second heat exchanger 3 a powerful ventilation system which would have an impact on costs and on electrical consumption.

The fact that the water used to cool the refrigerant comes from the chemical reaction within the fuel cell 10 allows in particular a constant supply of water without worrying about replenishment or filling. Indeed, water as well as air with a low O ₂ concentration are products of the chemical reaction taking place within the fuel cell 10.

As illustrated in FIG. 2, the additional heat exchanger 5 comprises:

° an enclosure 50 in which water from the chemical reaction within the fuel cell 10 is intended to be accumulated. This enclosure 50 comprises in particular an inlet pipe 501 of water resulting from the chemical reaction within the fuel cell 10 and a suction pipe 502 of water vapor disposed above the water level 500 in the enclosure 50, ° at least one tube 51 in which the refrigerant is able to circulate, said at least one tube 51 being able to be immersed in the water intended to be accumulated in the enclosure 50.

It is thus possible to summarize the thermal management of the fuel cell 10 in a method of managing a thermal management device 1 of the fuel cell 10, as described above. Said method comprising the following steps:

° recovery of water resulting from the chemical reaction within said fuel cell 10, ° immersion of part of the cooling circuit 100 in an enclosure 50 containing recovered water so as to exchange heat energy between on the one hand the refrigerant of the cooling circuit 100 and on the other hand the recovered water.

In the embodiment of the additional heat exchanger 5 illustrated in FIG. 2, the tubes 51 are flat tubes 510 arranged parallel to each other and connected to an inlet manifold 511 of refrigerant fluid at a first of their ends and to an outlet manifold 512 of refrigerant at their second end. It is however entirely possible to imagine, without departing from the scope of the invention, another type of tube 51, for example a serpentine tube 51 which is capable of being immersed in the water intended to be accumulated in enclosure 50.

In the present case, the flat tubes 510 have a general U-shape and the inlet 511 and outlet 512 collectors of coolant are arranged at the bottom of the enclosure 50.

When the tube or tubes 51 are immersed in water from the fuel cell 10 and the refrigerant circulates in said tubes 51, heat energy is transferred from the refrigerant to the water contained in the enclosure 50. This supply of heat energy causes the evaporation of a certain amount of water and this water vapor is evacuated by the suction pipe 502. The water level within the enclosure 50 will then have tendency to decrease and it is therefore important that in operation, the water level 500 within the enclosure 50 is maintained so that the tube or tubes 51 remain submerged.

The additional heat exchanger 5 can also include a purge device (not shown). This purge device makes it possible to empty the enclosure 50 of the water resulting from the chemical reaction within the fuel cell 10 in order to avoid problems of freezing in winter, which could damage said additional heat exchanger 5 .

As shown in Figures 1 and 3, the water circuit 200 may include a compressor 7 arranged downstream of the additional heat exchanger 5, in the direction of water circulation in the water circuit 200. More in particular, the compressor 7 is connected to the suction pipe 502 of the additional heat exchanger 5. This compressor 7 is capable of creating a vacuum within said additional heat exchanger 5, more precisely within the enclosure 50 Said compressor 7 is thus able to suck in water vapor in order to discharge it into the external environment. The decrease in pressure within the enclosure 50 due to the action of the compressor 7 allows a reduction in the boiling temperature of the water contained within said enclosure 50. Thus, a greater quantity of steam can be generated at temperatures below 100 ° C which is the boiling temperature of water at an average atmospheric pressure at sea level of 1.013 bar. It is thus possible to reduce the temperature of the refrigerant in the cooling circuit 100 to a temperature below 100 ° C. by reducing the pressure within the enclosure 50 of the additional heat exchanger 5.

For example, in order to have a boiling temperature of water at 90 ° C, the pressure within the enclosure 50 must be of the order of 0.7 bar. In this case, the compressor 7 must have a compression ratio of between 1 and 2, preferably between 1.3 and 1.7, more precisely of the order of 1.5.

For a boiling temperature of water at 80 ° C, the pressure within the enclosure 50 must be of the order of 0.47 bar. In this case the compressor 7 must have a compression ratio of between 1 and 3, preferably between 1.6 and 2.6, preferably between 1.9 and 2.3, more precisely of the order of 2 , 1.

The compressor 7 is preferably a centrifugal compressor with rotation speeds of between 80,000 rpm and 140,000 rpm in order to be able to reduce the pressure in the enclosure 50 of the additional heat exchanger 5 sufficiently.

If we resume the process for managing the thermal management device 1 mentioned above, said process can thus include an additional step of reducing the pressure within the enclosure 50 so as to reduce the boiling temperature of the water recovered.

The water circuit 200 may also include a buffer water tank 6 resulting from the chemical reaction within the fuel cell 10. This buffer water tank 6 is notably arranged upstream of said additional heat exchanger 5, in the direction of water circulation in the water circuit 200, between the fuel cell 10 and the additional heat exchanger 5. The buffer water tank 6 is more particularly connected to the supply line 501 d water from the additional heat exchanger 5 so that said additional heat exchanger 5 has a constant water supply when in operation.

The water in the buffer water tank 6 represents a potential for heat energy which can then be recovered by the refrigerant. Indeed, the enthalpy of evaporation of water at 90 ° C is of the order of 2277 kJ / kg and a reservoir of three liters of water can thus make it possible to maintain a cooling power of 22.7 kW for a period of 300 seconds with in particular a compressor 7 having a water vapor output flow of 0.01 kg / s and a volume flow input of 0.023 m ³ / s.

The water circuit 200 may comprise upstream of the buffer water tank 6 a device for controlling the water pressure 8, in the direction of circulation of the water in the water circuit 200. The control device of the water pressure 8, for example a valve, makes it possible in particular to control the filling of the buffer water tank 6, in particular when the temperature of the coolant arriving at the level of the additional heat exchanger 5 is less than or equal to 80 ° C, which is generally the case in “normal” use, and that there is therefore little or no evaporation of water within the enclosure 50. When the atmospheric pressure is less than the pressure of the water discharged at the fuel cell 10, an opening of the water pressure control device 8 allows passive filling of the buffer tank 6. When the atmospheric pressure is greater than or equal to the pressure of water discharged at the pile fuel 10, an opening of the water pressure control device 8 and a start-up of the compressor 7 to create a vacuum in the enclosure 50 and therefore in the buffer water tank 6, which allows filling of the buffer water tank 6.

According to a first embodiment illustrated in FIG. 1, the additional heat exchanger 5 can be arranged, in the cooling circuit 100, upstream of the second heat exchanger 3, between the first heat exchanger 2 and said second exchanger heat 3, in the direction of circulation of the refrigerant.

The refrigerant at the outlet of the first heat exchanger 2 is generally at a temperature greater than or equal to 95 ° C. when the fuel cell 10 is highly stressed, for example when the vehicle is uphill. The refrigerant therefore arrives at the additional heat exchanger at this temperature. If the pressure within the enclosure 50 of the additional heat exchanger 5 is of the order of 0.7 bar, the boiling temperature of the water resulting from the chemical reaction within the fuel cell 10 will be of the order of 90 ° C. With a flow of refrigerant of the order of 10,000 l / h in the tube or tubes 51, it is possible to lower the temperature of said refrigerant by approximately 2 ° C. at the outlet of the additional heat exchanger 5. The refrigerant is then less hot before entering the second heat exchanger 3 and the latter therefore needs less heat exchange capacity to reduce the temperature of said refrigerant to a temperature of around 85 ° C so that said coolant passes back into the first heat exchanger 2 to cool the fuel cell 10.

In this configuration and to reach such a pressure of the order of 0.7 bar, the compressor 7 must have a compression ratio of between 1 and 2, preferably between 1.3 and 1.7, more precisely order of 1.5.

According to a second embodiment illustrated in Figure 3, the additional heat exchanger 5 is arranged, in the cooling circuit 100, downstream of the second heat exchanger 3, between said second heat exchanger 3 and the first heat exchanger heat 2 in the direction of circulation of the refrigerant.

The refrigerant at the outlet of the first heat exchanger 2 is generally at a temperature greater than or equal to 95 ° C. when the fuel cell 10 is highly stressed, for example when the vehicle is uphill. The refrigerant therefore arrives at the second heat exchanger 3 at this temperature. The refrigerant undergoes a first temperature drop there depending on its heat exchange capacity, before passing into the additional heat exchanger 5. If the pressure within the enclosure 50 of the additional heat exchanger 5 is of the order of 0.47 bar, the boiling temperature of the water resulting from the chemical reaction within the fuel cell 10 will be of the order of 80 ° C. With a flow of refrigerant of the order of 10,000 l / h in the tube or tubes 51, it is possible to lower the temperature of said refrigerant by about 5 ° C. at the outlet of the additional heat exchanger 5. The refrigerant is then sufficiently cooled to return to the first heat exchanger 2 in order to cool the fuel cell 10. As the refrigerant undergoes a second cooling at the level of the additional heat exchanger 5, it is not necessary that the temperature at the outlet of the second heat exchanger 3 is low enough to cool the fuel cell.

In this configuration and to reach such a pressure of the order of 0.47 bar, the compressor 7 must have a compression ratio of between 1 and 3, preferably between 1.6 and 2.6, preferably between 1, 9 and 2.3, more precisely around 2.1

The present invention also relates to a method for thermal management of a fuel cell 10.

Thus, it can be seen that the thermal management device 1 of the fuel cell

10, due to the reuse of water from the chemical reaction within the fuel cell, allows better cooling of said cell which avoids having to increase the heat exchange capacity of the second heat exchanger 3 compared to a so-called conventional front face heat exchanger, for example used for other types of motorization.

Claims (17)

1. A thermal management device (1) for a fuel cell (10), said thermal management device (1) comprising a cooling circuit (100) inside which a cooling fluid and / or a heat-transfer fluid is capable of circulating and including: ° a pump (4), ° a first heat exchanger (2) disposed at the fuel cell (10), ° a second heat exchanger (3) placed in an air flow so as to cool the fluid refrigerant and / or the heat transfer fluid from the first heat exchanger (2), characterized in that said thermal management device (1) comprises a water circuit (200) resulting from the chemical reaction within the cell to fuel (10), and an additional heat exchanger (5) configured to exchange heat energy between on the one hand the refrigerant and / or the coolant of the cooling circuit (100) and on the other hand water from said water circuit (200). 2. A thermal management device (1) according to claim 1, characterized in that the additional heat exchanger (5) is arranged, in the cooling circuit (100), upstream of the second heat exchanger (3), between the first heat exchanger (2) and said second heat exchanger (3) in the direction of circulation of the refrigerant and / or the heat transfer fluid. 3. A thermal management device (1) according to claim 1, characterized in that the additional heat exchanger (5) is arranged, in the cooling circuit (100), downstream of the second heat exchanger (3), between said second heat exchanger (3) and the first heat exchanger (2) in the direction of circulation of the refrigerant and / or the heat transfer fluid. 4. A thermal management device (1) according to one of the preceding claims, characterized in that the water circuit (200) comprises a buffer water tank (6) resulting from the chemical reaction within the cell to fuel (10), said buffer water tank (6) being arranged upstream of said additional heat exchanger (5), in the direction of water circulation in the water circuit (200). 5. A thermal management device (1) according to the preceding claim, characterized in that the water circuit (200) comprises upstream of the buffer water tank (6) a device for controlling the water pressure (8 ), in the direction of water circulation in the water circuit (200). 6. A thermal management device (1) according to one of the preceding claims, characterized in that the water circuit (200) comprises a compressor (7) disposed downstream of the additional heat exchanger (5), in the direction of water circulation in the water circuit (200), said compressor (7) being able to create a vacuum within said additional heat exchanger (5) and to suck water vapor within said additional heat exchanger (5) in order to discharge it into the external environment. 7. A thermal management device (1) according to claim 6 in combination with claim 2, characterized in that the compressor (7) has a compression ratio between 1 and 2, preferably between 1.3 and 1.7 . 8. A thermal management device (1) according to claim 6 in combination with claim 3, characterized in that the compressor (7) has a compression ratio of between 1 and 3, preferably between 1.6 and 2.6 , preferably between 1.9 and 2.3. 9. Thermal management device (1) according to one of the preceding claims, characterized in that the additional heat exchanger (5) comprises: ° an enclosure (50) in which water resulting from the chemical reaction within the fuel cell (10) is intended to be accumulated, said enclosure (50) comprising a water inlet pipe (501) resulting from the chemical reaction within the fuel cell (10) and a suction pipe (502) of water vapor disposed above the water level (500) in the enclosure (50), ° at least one tube (51) in which the refrigerant and / or the heat transfer fluid is able to circulate, said at least one tube (51) being able to be immersed in the water intended to be accumulated in the enclosure (50 ). 10. A thermal management device (1) according to the preceding claim, characterized in that the tubes (51) in which the refrigerant and / or the heat transfer fluid is able to circulate, are flat tubes (510) arranged parallel to each other. to the others and connected to an inlet manifold (511) of coolant and / or heat transfer fluid at a first of their ends and to an outlet manifold (512) of coolant and / or heat transfer fluid at their second end . 11. Thermal management device (1) according to the preceding claim, characterized in that the flat tubes (510) have a general U-shape and that the inlet (511) and outlet (512) manifolds of refrigerant and / or heat transfer fluid are arranged at the bottom of the enclosure (50). 12. A thermal management device (1) according to one of claims 9 to 11 in combination with one of claims 4 or 5, characterized in that the buffer water tank (6) is connected to the line of water inlet (501) from the additional heat exchanger (5). 13. A thermal management device according to one of claims 9 to 12 in combination with claim 6, characterized in that the compressor (7) is connected to the suction pipe (502) of water vapor from the heat exchanger (5). 14. A thermal management device (1) according to one of claims 9 to 13, characterized in that in operation, the water level (500) within the enclosure (50) is maintained so that the or the tubes (51) remain submerged. 15. A thermal management device (1) according to one of claims 9 to 14, characterized in that the additional heat exchanger (5) comprises a purge device so as to be able to empty the enclosure (50) of the water from the chemical reaction within the fuel cell (10). 16. A method of managing a thermal management device (1) for a fuel cell (10), said thermal management device (1) comprising a cooling circuit (100) inside which a refrigerant and / or a heat transfer fluid is able to circulate and comprising: ° a pump (4), ° a first heat exchanger (2) disposed at the fuel cell (10), ° a second heat exchanger (3) placed in an air flow so as to cool the fluid refrigerant and / or heat transfer fluid from the 5 first heat exchanger (2), said method comprising the following steps: ° recovery of water resulting from the chemical reaction within said fuel cell (10), ° immersion of part of the cooling circuit (100) in an enclosure 10 (50) containing water recovered so as to exchanging heat energy between on the one hand the refrigerant and / or the coolant of the cooling circuit (100) and on the other hand the recovered water. 17. Management method according to the preceding claim, characterized in that it comprises an additional step of reducing the pressure within the enclosure (50) so as to reduce the boiling temperature of the recovered water. 1/2