Fuel cell system with circulation means

Abstract

The invention relates to a fuel cell system (2), which comprises: - a fuel cell stack (6) comprising an anode and a cathode; - a housing (8), in which the stack is arranged, having a ventilation inlet (10) and a ventilation outlet (12); - a compression device (18) arranged upstream of an inlet pipe (7a) of the cathode; - a water separator (24) connected to an outlet pipe (7b) of the cathode and configured to separate an incoming cathode gas flow (26) into a first outgoing flow comprising water-rich air, exiting via a first outlet (28a) of the water separator (24), and a second outgoing flow comprising water-poor air, exiting via a second outlet (28b) of the water separator (24); - an ejector (30) comprising a primary inlet (32a) connected to the first outlet (28a) of the water separator (24) and a secondary inlet (32b) connected to the ventilation outlet (12) of the housing (8); and - a turbine (38) arranged downstream of the second outlet (28b) of the water separator (24).

Description

Fuel cell system with circulation means

[0001] The invention relates to the field of fuel cells such as proton exchange membrane fuel cells. More specifically, the invention relates to a fuel cell system intended to equip a mobile element such as a vehicle, as well as to a vehicle comprising such a fuel cell system.

[0002] A proton exchange membrane fuel cell, commonly abbreviated as "PEMFC" from the English term "polymer electrolyte membrane fuel cell", typically comprises a membrane electrode arranged between two unipolar half-plates. A membrane electrode comprises an electrolytic solution contained in a proton-conducting membrane arranged between an anode and a cathode. A set of fuel cells forms what is commonly called a fuel cell stack. In a fuel cell stack, several fuel cells are connected in parallel in the stack and are electrically connected in series so that the fuel cell stack produces sufficient electrical energy.In a known manner, the anode is supplied with a hydrogen-rich gas (H2) and the cathode is supplied with a gas containing oxygen (O2), atmospheric air for example, in order to produce electricity and, in particular, water at a cathode outlet, water being a reaction product of each fuel cell. In the case where atmospheric air is used as the oxygen-containing gas, nitrogen is another product present at an anode outlet. Indeed, in this case, the nitrogen present in the air migrates from the cathode to the anode through the electrode membrane. Document JP 2013 037826 A discloses an example of a fuel cell system having this mode of operation.

[0003] Since hydrogen is particularly volatile, it is possible for a quantity of hydrogen circulating in the fuel cell stack to escape from it. It then spreads into a housing in which the fuel cell stack is arranged and remains confined within this housing. Although the risk of such a leak occurring is generally low, an accumulation of hydrogen inside the housing constitutes a considerable danger that must be avoided because it could cause an explosion in the event of combustion.

[0004] To this end, it is known from the prior art to constantly ventilate the housing of the fuel cell stack, for example using a fan arranged to generate an air flow passing through the housing to evacuate the hydrogen therefrom. This thus makes it possible to prevent the hydrogen concentration inside the housing from reaching dangerous values.

[0005] The prior art fan thus overcomes the danger caused by potential hydrogen leaks in the fuel cell stack housing, but this comes with new problems. Indeed, the fan needs to be supplied with electrical energy to operate, so its presence has the indirect effect of lowering the overall energy efficiency of the fuel cell system. In addition, the fan is a relatively bulky component that can be complex to arrange in the fuel cell system, especially if the system is fitted to a vehicle, itself comprising drastic space constraints. Furthermore, the presence of the fan and its electrical connections significantly increases the manufacturing cost of the fuel cell system, which is generally preferable to avoid.

[0006] The invention aims in particular to remedy these drawbacks by providing a fuel cell system preventing the accumulation of hydrogen in the housing of the fuel cell stack using means which are less energy-intensive, more compact and less expensive than those of the prior art.

[0007] To this end, the invention relates in particular to a fuel cell system comprising:

[0008] - a fuel cell stack comprising an anode and a cathode,

[0009] - a housing, in which the stack of fuel cells is arranged, having a ventilation inlet and a ventilation outlet,

[0010] - a compression device arranged upstream of a cathode inlet pipe,

[0011] - a water separator connected to an outlet pipe of the cathode and configured to separate an incoming cathode gas stream into a first outgoing stream comprising air rich in liquid water, exiting through a first outlet of the water separator, and a second outgoing stream comprising air lean in liquid water, exiting through a second outlet of the water separator,

[0012] - an ejector comprising a primary inlet connected to the first outlet of the water separator and a secondary inlet connected to the ventilation outlet of the housing, and

[0013] - a turbine arranged downstream of the second outlet of the water separator.

[0014] Thus, the fuel cell system according to the invention uses one of the flows leaving the water separator to generate, using the ejector, a venturi effect continuously sucking the gas contained in the housing of the fuel cell stack through the secondary inlet of the ejector. Since the water separator is a component already present in a conventional system, only the ejector constitutes an additional component compared to such a system. Since the ejector is a passive component, i.e. it does not require an energy supply to operate, it has no negative impact on the energy efficiency of the system, unlike the fan of the prior art. Furthermore, the ejector is much more compact than the fan and does not require electrical connections, so it is simpler to arrange it in the fuel cell system.Finally, the ejector is a less expensive component than the prior art fan, and thus helps to reduce the manufacturing cost of the fuel cell system.

[0015] The presence of the turbine makes it possible to recover part of the kinetic energy of the second flow leaving the water separator, which contributes to increasing the energy efficiency of the fuel cell system. In other words, the presence of the turbine allows the system to utilize both the first flow leaving through the first outlet of the water separator, by ventilating the housing, and the second flow leaving through the second outlet of the water separator, by recovering part of the kinetic energy of this second flow.

[0016] Advantageously, the turbine is mounted on a shaft common to the compression device and to an electric motor connected to the compression device.

[0017] The kinetic energy recovered by the second flow turbine thus helps to drive the electric motor. This reduces the electrical energy consumed by the electric motor to power the compression device to compress the air coming from the air supply means. Therefore, the turbine thus mounted reduces the energy consumption necessary for the operation of the fuel cell system.

[0018] Advantageously, the fuel cell system further comprises a heat exchanger arranged between the compression device and the cathode inlet pipe.

[0019] This allows the temperature parameters of the cathode gas flow feeding the cathode inlet line to be controlled, helping to optimize the performance of the fuel cell system.

[0020] Advantageously, the ventilation inlet of the housing is connected to a first supply point located upstream of the compression device.

[0021] If the first flow leaving the water separator has a sufficiently high flow rate, the venturi effect generated by its passage through the ejector is powerful enough to draw air through the housing, via the secondary inlet of the ejector, before it is compressed by the compression device. This avoids unnecessary compression of this volume of air and therefore a reduction in the energy efficiency of the fuel cell system.

[0022] Advantageously, the fuel cell system further comprises a non-return valve arranged between the ventilation inlet of the housing and the first supply point.

[0023] This prevents any untimely leakage of hydrogen contained in the housing into the rest of the fuel cell system, using simple and passive means.

[0024] Advantageously, the ventilation inlet of the housing is connected to a second supply point located downstream of the heat exchanger.

[0025] It may happen that the first flow out of the water separator has a flow rate that is not large enough to generate a venturi effect by its passage through the ejector powerful enough to draw air through the housing, through the secondary inlet of the ejector, before it is compressed by the compression device. This is the case when the fuel cell system is operating at low speed. In this case, the ejector is allowed to draw compressed air through the compression device, which is possible even with a relatively weak venturi effect.

[0026] Preferably, the fuel cell system further comprises a valve arranged between the ventilation inlet of the housing and the second supply point.

[0027] This allows the opening and closing of access to the second supply point to be simply controlled. For example, the opening and closing of the valve can be dynamically controlled based on a measurement of the flow rate of the first stream leaving the water separator and a comparison of this measured value with a predetermined threshold value.

[0028] Preferably, the valve is a proportional valve configured to control the flow rate at the ventilation inlet of the housing based on a target flow rate value.

[0029] This allows for finer management of the case's ventilation.

[0030] According to an alternative embodiment of the invention, the fuel cell system further comprises a three-way valve arranged between the first supply point, the second supply point and the ventilation inlet of the housing.

[0031] The check valve and valve mentioned above are thus replaced by a three-way valve that can perform the same functions as the check valve and valve. This reduces the number of components in the fuel cell system by one, which helps simplify it, while allowing better control over the selection of the active feed point. The three-way valve, for example, is of the proportional and non-mixing type, so it is a standard component that does not require any special modifications for its operation.

[0032] Advantageously, the fuel cell system further comprises a humidifier arranged between the heat exchanger and the cathode inlet pipe.

[0033] This allows for management of the humidification of the cathode gas flow feeding the cathode inlet pipe, which helps to improve the operation, efficiency and lifetime of the fuel cell system.

[0034] Advantageously, the ejector is a venturi pump or suction jet pump.

[0035] The ejector is thus made with simple means.

[0036] The invention also provides a vehicle comprising an electric powertrain and an electrical energy storage element, comprising a fuel cell system as defined above.

[0037] The invention also provides a method for managing a fuel cell system, the fuel cell system comprising:

[0038] - a fuel cell stack comprising an anode and a cathode,

[0039] - a housing, in which the stack of fuel cells is arranged, having a ventilation inlet and a ventilation outlet,

[0040] - a compression device arranged upstream of a cathode inlet pipe,

[0041] - a water separator connected to an outlet pipe of the cathode, configured to separate an incoming cathode gas stream into a first outgoing stream comprising air rich in liquid water, exiting through a first outlet of the water separator, and a second outgoing stream comprising air lean in liquid water, exiting through a second outlet of the water separator,

[0042] - an ejector comprising a primary inlet connected to the first outlet of the water separator and a secondary inlet connected to the ventilation outlet of the housing, and

[0043] - a turbine arranged downstream of the second outlet of the water separator,

[0044] the method implementing the step in which the ejector sucks the gas contained in the housing by venturi effect caused by the circulation of the flow entering through the primary inlet through the ejector.

[0045] Advantageously, the fuel cell system further comprises a heat exchanger arranged between the compression device and the cathode inlet pipe,

[0046] in which either the ventilation inlet of the housing is connected to a first supply point located upstream of the compression device via a non-return valve and to a second supply point located downstream of the heat exchanger via a valve,

[0047] either the ventilation inlet of the housing is connected, via a three-way valve, on the one hand to the first supply point located upstream of the compression device and on the other hand to the second supply point located downstream of the heat exchanger.

[0048] According to a first embodiment of the invention, the valve is closed so that the secondary inlet of the ejector is supplied with gas from the first supply point.

[0049] According to a second embodiment of the invention, the valve is opened so that the secondary inlet of the ejector is supplied with gas from the second supply point.

[0050] As indicated above, the first and second feed points allow to take into account the flow rate of the first stream leaving the separator and the power of the venturi effect generated in the ejector, which makes possible finer management of the ventilation of the housing.

[0051] The invention also provides a computer program comprising instructions which, when the program is executed by a computer, cause the latter to implement the steps of the method as defined above, as well as a computer-readable recording medium comprising instructions which, when executed by a computer, cause the latter to implement the steps of the method as defined above. Brief description of the figures

[0052] The invention will be better understood on reading the following description, given solely by way of example and with reference to the appended drawings in which:

[0053] is a schematic view of a fuel cell system, according to one embodiment of the invention, in which a method for managing the latter is implemented according to a first embodiment,

[0054] is a schematic view of a fuel cell system, according to one embodiment of the invention, in which a method for managing the latter is implemented according to a second embodiment, and

[0055] is a schematic view of a fuel cell system according to an alternative embodiment of the invention. Detailed description

[0056] In the following description, the terms "downstream" and "upstream" refer to the direction of flow of the various fluids in the fuel cell system, these directions of flow being represented by single arrows in the figures.

[0057] A fuel cell system 2 according to an embodiment of the invention is shown, which in this case equips a vehicle 4 of the type comprising an electric powertrain and an electrical energy storage element. The fuel cell system 2 comprises a fuel cell stack 6 comprising an anode and a cathode, the latter being in particular provided with a cathode inlet pipe 7a and a cathode outlet pipe 7b. What enters and leaves the cathode via the pipes 7a and 7b is a cathode gas. The cathode gas is a mixture of air and water. As indicated above, the operating principle of the fuel cell stack for the production of electrical energy is known per se, so it will not be described in more detail below. The fuel cell stack 6 is housed in a housing 8 having a ventilation inlet 10 and a ventilation outlet 12.Disregarding the ventilation inlet 10 and the ventilation outlet 12, the housing 8 defines a sealed volume encompassing the entire fuel cell stack 6.

[0058] The fuel cell system 2 comprises means 14 for supplying a gas containing oxygen, for example atmospheric air, to the inlet pipe 7a of the cathode. Downstream of the air supply means 14, the fuel cell system 2 comprises a filter 16 for filtering residues possibly contained in the air coming from the air supply means 14 in order to prevent their intrusion into the system.

[0059] Downstream of the filter 16, the fuel cell system 2 comprises a compression device 18, for example an electric turbocharger, configured to compress the air coming from the air supply means 14 before it is supplied to the inlet pipe 7a of the cathode. The compression device 18 is connected to an electric motor 19 configured to supply energy to the compression device 18 necessary for compressing the air coming from the air supply means 14. Downstream of the compression device 18, the fuel cell system 2 comprises a heat exchanger 20, for example a charge air cooler, also called a "charge air cooler" in English, configured to heat the air before it is supplied to the inlet pipe 7a of the cathode.The fuel cell system 2 comprises a humidifier 22, arranged between the heat exchanger 20 and the cathode inlet line 7a, configured to humidify the air before it is supplied to the cathode inlet line 7a. Compressing, heating and humidifying the air before it is supplied to the cathode inlet line 7a makes it possible to optimize the operation of the fuel cell stack 6.

[0060] At the cathode, water is produced by the reaction between oxygen in the air and hydrogen ions from the anode, such that the cathode gas exiting through the cathode outlet line 7b comprises water-enriched and oxygen-depleted air. Downstream of the cathode outlet line 7b, the fuel cell system 2 comprises a water separator 24 configured to separate the incoming cathode gas stream 26 into a first outgoing stream comprising liquid water-rich air, exiting through a first outlet 28a of the water separator 24, and a second outgoing stream comprising liquid water-lean air, exiting through a second outlet 28b of the water separator 24.

[0061] Downstream of the first outlet 28a of the water separator 24, the fuel cell system 2 comprises an ejector 30 comprising a primary inlet 32a connected to the first outlet 28a of the water separator 24 and a secondary inlet 32b connected to the ventilation outlet 12 of the housing 8. The ejector 30 further comprises an ejection outlet 34 opening onto an exhaust pipe 36 of the fuel cell system 2 exiting therefrom. The ejector 30 is here a venturi pump or a suction jet pump.

[0062] Downstream of the second outlet 28b of the water separator 24, the fuel cell system 2 comprises a turbine 38 configured to recover a portion of the kinetic energy of the second flow exiting through the second outlet 28b of the water separator 24 comprising air low in liquid water before it is discharged towards the exhaust pipe 36. In the embodiment as illustrated in, the turbine 38 is mounted on a shaft common to the electric motor 19 and to the compression device 18. In this way, the kinetic energy recovered by the turbine 38 makes it possible to drive the electric motor 19 and therefore to reduce the electrical energy that it consumes to power the compression device 18 to compress the air coming from the air supply means 14. It is thus understood that the turbine 38 makes it possible to reduce the energy consumption necessary for the operation of the fuel cell system 2.According to an alternative embodiment of the invention, the turbine is not mounted on a shaft common to the electric motor and the compression device, in which case the kinetic energy recovered by the turbine is used differently; it can, for example, be supplied to other components of the vehicle equipped with the fuel cell system.

[0063] The ventilation inlet 10 of the housing 8 is connected in parallel to two air supply points of the fuel cell system 2. A first supply point 40 is located upstream of the compression device 18 and downstream of the filter 16. A non-return valve 42 is arranged between the ventilation inlet 10 of the housing 8 and the first supply point 40 and is configured to prevent any circulation of fluid from the ventilation inlet 10 of the housing 8 to the first supply point 40. A second supply point 44 is located downstream of the heat exchanger 20 and upstream of the humidifier 22. A valve 46 is arranged between the ventilation inlet 10 of the housing 8 and the second supply point 44. The valve 46 here comprises a proportional valve configured to control the flow rate at the ventilation inlet 10 of the housing 8 as a function of a target flow rate value.The valve 46 is, for example, a valve actuated by a hydraulic, pneumatic or, preferably, electric actuator.

[0064] We will now describe a method for managing the fuel cell system 2 allowing the ventilation of the housing 8.

[0065] The passage of the first flow leaving the water separator 24 into the ejector 30 through its primary inlet 32a generates, by venturi effect, a depression inside the latter which is all the greater the greater the flow rate of the first flow leaving the water separator 24. This depression makes it possible to suck in the gas contained in the housing 8, provided that this depression is sufficiently great to allow the gas contained in the housing to be moved through the secondary inlet 32b of the ejector 30.

[0066] According to a first embodiment of this method illustrated in, the flow rate of the first flow leaving the water separator 24 is greater than a predetermined value such that the depression generated by the venturi effect in the ejector 30 is sufficiently large to allow the gas contained in the housing 8 to be sucked in through the secondary inlet 32b of the ejector 30, without it being necessary to increase its pressure. This first embodiment corresponds for example to the situation in which the fuel cell system 2 operates at high speed.

[0067] Under these conditions, the valve 46 is closed or kept closed so that the gas sucked from the housing 8 is renewed by air coming from the first supply point 40 free of hydrogen, or at least having a negligible concentration of hydrogen, as indicated by the double arrow shown in the figure. The gas sucked from the housing 8 enters the ejector 30 through the secondary inlet 32b, is mixed with the first flow leaving the water separator 24, and leaves the ejector 30 through the ejection outlet 34 to be discharged into the exhaust pipe 36.

[0068] A second embodiment of the method for managing the fuel cell system 2 allowing the ventilation of the housing 8 has been shown. The system itself is the same as that illustrated in. According to the second embodiment of the method, the flow rate of the first flow leaving the water separator 24 is lower than the predetermined value, such that the depression generated by the venturi effect in the ejector 30 is not sufficiently large to allow the gas contained in the housing 8 to be sucked in through the secondary inlet 32b of the ejector 30 without it being necessary to increase its pressure. This second embodiment corresponds for example to the situation in which the fuel cell system 2 operates at low speed.

[0069] Under these conditions, the valve 46 is opened or kept open so that the housing 8 is in communication with the outlet of the heat exchanger 20 and, above all, the outlet of the compression device 18. This has the effect of increasing the gas pressure inside the housing 8 sufficiently so that the depression generated by the venturi effect in the ejector 30 allows it to suck, through the secondary inlet 32b, the gas from the housing 8, which is then renewed by air coming from the second supply point 44 which is also free of hydrogen, as indicated by the double arrow shown in the figure. The opening of the proportional valve 46 is controlled to control the flow rate at the ventilation inlet 10 of the housing 8 as a function of a target flow rate value. The target flow rate value is determined as a function of operating parameters of the fuel cell system 2 such as, for example, the pressure at the inlet of the system or the temperature at the inlet of the system.In the same way as according to the first embodiment, the gas sucked from the housing 8 enters the ejector 30 through the secondary inlet 32b, is mixed with the first flow leaving the water separator 24, and leaves the ejector 30 through the ejection outlet 34 to be discharged into the exhaust pipe 36.

[0070] A fuel cell system 2 according to an alternative embodiment of the invention is shown. This system differs from that illustrated in Figures 1 and 2 only in that the non-return valve and the valve are replaced by a three-way valve 48 arranged between the first supply point 40, the second supply point 44 and the ventilation inlet 10 of the housing 8. The three-way valve 48 is configured to select an air passageway connecting the ventilation inlet 10 of the housing 8 with, alternatively, the first supply point 40 or the second supply point 44. It is thus understood that this fuel cell system allows the implementation of a method for managing it identical to that presented above in relation to Figures 1 and 2.

[0071] The invention is particularly applicable to equipment that is both mobile, such as road vehicles including cars and trucks, rail vehicles, marine vehicles, aircraft and spacecraft, and stationary, such as power plants or generator sets. List of references

[0072] 2: Fuel cell system4: Vehicle6: Fuel cell stack7a: Cathode inlet pipe7b: Cathode outlet pipe8: Housing10: Ventilation inlet12: Ventilation outlet14: Air supply means16: Filter18: Compression device19: Electric motor20: Heat exchanger22: Humidifier24: Water separator26: Incoming cathode gas flow28a: First water separator outlet28b: Second water separator outlet30: Ejector32a: Primary ejector inlet32b: Secondary ejector inlet34: Ejection outlet36: Exhaust pipe38: Turbine40: First feed point42: Check valve44: Second feed point46: Valve48: Three-way valve

Claims

Fuel cell system (2), characterized in that it comprises:- a fuel cell stack (6) comprising an anode and a cathode,- a housing (8), in which the fuel cell stack is arranged, having a ventilation inlet (10) and a ventilation outlet (12),- a compression device (18) arranged upstream of an inlet pipe (7a) of the cathode,- a water separator (24) connected to an outlet pipe (7b) of the cathode and configured to separate an incoming cathode gas flow (26) into a first outgoing flow comprising air rich in liquid water, exiting through a first outlet (28a) of the water separator (24), and a second outgoing flow comprising air poor in liquid water, exiting through a second outlet (28b) of the water separator (24),- an ejector (30) comprising a primary inlet (32a) connected to the first outlet (28a) of the water separator (24) and a secondary inlet (32b) connected to the ventilation outlet (12) of the housing (8), and - a turbine (38) arranged downstream of the second outlet (28b) of the water separator (24)., Fuel cell system (2) according to claim 1, further comprising a heat exchanger (20) arranged between the compression device (18) and the inlet pipe (7a) of the cathode. Fuel cell system (2) according to claim 1 or 2, wherein the ventilation inlet (10) of the housing (8) is connected to a first supply point (40) located upstream of the compression device (18). Fuel cell system (2) according to claim 3, further comprising a non-return valve (42) arranged between the ventilation inlet (10) of the housing (8) and the first supply point (40). Fuel cell system (2) according to any one of claims 2 to 4, wherein the ventilation inlet (10) of the housing (8) is connected to a second supply point (44) located downstream of the heat exchanger (20). Fuel cell system (2) according to claim 5, further comprising a valve (46) arranged between the ventilation inlet (10) of the housing (8) and the second supply point (44). The fuel cell system (2) of claim 6, wherein the valve (46) is a proportional valve configured to control the flow rate at the ventilation inlet (10) of the housing (8) based on a target flow rate value. A fuel cell system according to claim 5 taken in combination with claim 3, further comprising a three-way valve (48) arranged between the first feed point (40), the second feed point (44) and the ventilation inlet (10) of the housing (8). Fuel cell system (2) according to any one of claims 2 to 8, further comprising a humidifier (22) arranged between the heat exchanger (20) and the cathode inlet pipe (7a). A fuel cell system (2) according to any preceding claim, wherein the ejector (30) is a venturi pump or suction jet pump. Vehicle (4) comprising an electric powertrain and an electrical energy storage element, characterized in that the vehicle comprises a fuel cell system (2) according to any one of the preceding claims. A method for managing a fuel cell system (2), characterized in that the fuel cell system comprises:- a fuel cell stack (6) comprising an anode and a cathode,- a housing (8), in which the fuel cell stack (6) is arranged, having a ventilation inlet (10) and a ventilation outlet (12),- a compression device (18) arranged upstream of an inlet pipe (7a) of the cathode,- a water separator (24) connected to an outlet pipe (7b) of the cathode, configured to separate an incoming cathode gas flow (26) into a first outgoing flow comprising air rich in liquid water, exiting through a first outlet (28a) of the water separator (24), and a second outgoing flow comprising air poor in liquid water, exiting through a second outlet (28b) of the water separator (24),- an ejector (30) comprising a primary inlet (32a) connected to the first outlet (28a) of the water separator (24) and a secondary inlet (32b) connected to the ventilation outlet (12) of the housing (8), and - a turbine (38) arranged downstream of the second outlet (28b) of the water separator (24), the method implementing the step according to which the ejector (30) sucks the gas contained in the housing (8) by venturi effect caused by the circulation of the flow entering through the primary inlet (32a) through the ejector (30)., A method for managing a fuel cell system (2) according to the preceding claim, wherein the fuel cell system (2) further comprises a heat exchanger (20) arranged between the compression device (18) and the inlet pipe (7a) of the cathode, wherein:a) the ventilation inlet (10) of the housing (8) is connected to a first supply point (40) located upstream of the compression device (18) via a non-return valve (42) and to a second supply point (44) located downstream of the heat exchanger (20) via a valve (46), orb) the ventilation inlet (10) of the housing (8) is connected, via a three-way valve (48), on the one hand to the first supply point (40) located upstream of the compression device (18) and on the other hand to the second supply point (44) located downstream of the heat exchanger (20). Method for managing a fuel cell system according to variant a) of claim 13, in which the valve (46) is closed so that the secondary inlet (32b) of the ejector (30) is supplied with gas coming from the first supply point (40). Method for managing a fuel cell system according to variant a) of claim 13, in which the valve (46) is opened so that the secondary inlet (32b) of the ejector (30) is supplied with gas coming from the second supply point (44). A computer program comprising instructions which, when the program is executed by a computer, cause the computer to implement the steps of the method according to any one of claims 12 to 15. A computer-readable recording medium comprising instructions which, when executed by a computer, cause the computer to carry out the steps of the method according to any one of claims 12 to 15.

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