Electrical power supply system for an aircraft propulsion electric motor comprising a fuel cell

Abstract

An electrical power supply system (1) for at least one aircraft propulsion electric motor (M), the electrical power supply system (1) comprising a fuel cell (2), configured to be powered by an air stream (FA) and a hydrogen stream (FH), configured to electrically supply an electrical distribution box (3) configured to be connected to said propulsion electric motor (M), the fuel cell (2) comprising at least one first electrochemical line (LA) and a second electrochemical line (LB) electrically connected in parallel, each electrochemical line (LA, LB) comprising at least two independent stacks (E1-E8) electrically connected in series, each stack (E1-E8) comprising a plurality of electrochemical cells. Abstract figure: Figure 2

Description

Title of the invention: Electrical power supply system for an aircraft propulsion electric motor comprising a fuel cell. Technical field

[0001] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0002] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0003] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0004] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0005] It has thus been proposed to equip an aircraft with a plurality of electric propulsion motors to enable the aircraft's propulsion. As is known, the aircraft includes at least one fuel cell to electrically power a plurality of electric propulsion motors. In practice, depending on the aircraft's flight phase (takeoff, cruise, taxiing, etc.), the power required by the electric propulsion motors varies, which translates, for the fuel cell, into a variable electrical load. To enable the supply of an electrical load Variable power requirements mean that multiple fuel cells coupled with an electronic power regulation device are used to meet the aircraft's needs while maintaining the fuel cells within a high-efficiency operating range. Integrating an electronic power regulation device significantly increases the volume and mass, which is particularly detrimental in an aeronautical context. In practice, it is complex to obtain fuel cells that precisely meet the requirements, and oversized fuel cells are generally used, further increasing mass and size.

[0006] The invention thus aims to eliminate at least some of these drawbacks. PRESENTATION OF THE INVENTION

[0007] The invention relates to an electrical power supply system for at least one aircraft propulsion electric motor, the electrical power supply system comprising a fuel cell, configured to be powered by an airflow and by a hydrogenflow, configured to electrically power an electrical distribution box configured to be connected to said propulsion electric motor.

[0008] The system is remarkable in that the fuel cell comprises at least a first electrochemical line and a second electrochemical line mounted electrically in parallel, each electrochemical line comprising at least two independent stacks mounted electrically in series, each stack comprising a plurality of electrochemical cells.

[0009] Thanks to the invention, there is great flexibility in the choice of stacks and avoids the need for a fuel cell with a single, oversized stack, which negatively impacts mass and size. The modular design of the fuel cell also ensures precise positioning of the center of gravity to improve stability and optimize the overall size. The use of several independent stacks facilitates maintenance while allowing for high voltage levels.

[0010] In one aspect, the power supply system comprises a single fuel cell. The use of a single fuel cell reduces the size and eliminates the need for an electronic power regulation device.

[0011] Preferably, each electrochemical line comprises three or four independent stacks connected electrically in series. Such an electrochemical line ensures significant flexibility in terms of maintenance and space requirements while maintaining reduced complexity.

[0012] Preferably, the fuel cell comprises only a first electrical line A two-stage chemical line and a second electrochemical line are electrically connected in parallel. This provides flexibility and redundancy.

[0013] In one aspect, the electrical distribution box is free of a power regulation device. This simplifies the electrical generation system while reducing mass and size.

[0014] According to one aspect, the power supply system includes an air supply circuit configured to supply the fuel cell with an airflow, the air supply circuit including an upstream air inlet. The airflow circulates from upstream to downstream.

[0015] According to one aspect, the electrical distribution box is positioned upstream of the fuel cell. This allows it to be kept away from the fuel cell connectors located downstream.

[0016] According to one aspect, the air supply circuit includes an air circulation pump positioned vertically below the fuel cell.

[0017] According to one aspect, the fuel cell comprises an upper part including at least one hydrogen connector and a lower part including at least one air connector. This optimizes the overall size while allowing segregation into air (in the lower part) and hydrogen (in the upper part) by taking advantage of the fact that air is heavier than hydrogen.

[0018] According to one aspect, the power supply system comprises a support structure having a lattice shape defining a main housing in which the fuel cell is mounted. This allows the fuel cell to be ventilated while optimally protecting it against shocks.

[0019] According to one aspect, the power supply system includes an auxiliary electrical box configured to power the air circulation pump and, preferably, a cooling circulation pump.

[0020] According to one aspect, the fuel cell includes a collector configured to be supplied by the air flow and by the hydrogen flow, the collector being connected to the two electrochemical lines. This simplifies the structure of the fuel cell.

[0021] The collector also provides greater compactness while reducing the mass of the entire electrochemical line assembly. The collector also reduces the number and size of possible hydrogen leakage paths. Furthermore, the stacks can be optimally tilted during operation.

[0022] According to one aspect, each electrochemical line is configured to be powered independently. The power generated by each electrochemical line can thus be regulated independently.

[0023] The invention also relates to an assembly consisting of a power supply system, as previously described, and at least one aircraft propulsion electric motor connected to the electrical distribution box. In one aspect, the aircraft's electric propulsion motor is connected directly to the electrical distribution box. This eliminates the need for an electronic power regulation device.

[0024] The invention further relates to an aircraft comprising at least one assembly, as previously described, for enabling the propulsion of said aircraft.

[0025] The invention also relates to a method for supplying electrical power to at least one aircraft propulsion electric motor connected to an electrical power supply system, as described above, the method comprising steps consisting of: • Supply the fuel cell with an airflow and a hydrogenflow to electrically power the electrical distribution box connected to said propulsion electric motor, and • Regulate at least the airflow in each electrochemical line in order to regulate the electrical power supplied by the fuel cell.

[0026] Also presented is a manifold for a fuel cell configured to be powered by an air flow and a hydrogen flow, the fuel cell comprising at least two stacks, each stack comprising a plurality of electrochemical cells, the manifold extending longitudinally along a manifold axis and vertically along a vertical axis, the manifold defining a body comprising a first lateral face configured to interface with at least one stack and a second lateral face configured to interface with at least one stack, the manifold comprising a connection face comprising: • a first hydrogen connector configured to power at least one stack on the first side face, • a first air connector configured to supply at least one stack of the first side face.

[0027] Such a collector makes it possible to spatially distribute several stacks in order to increase compactness and reduce bulk.

[0028] According to one aspect, the hydrogen connectors are located vertically above the air connectors. This prevents any mixing of fluids and facilitates the handling of any leaks.

[0029] According to one aspect, each lateral face is connected to a common end plate to which all the stacks interfaced with said lateral face are connected. The use of a common end plate reduces leakage paths and increases structural strength.

[0030] According to one aspect, the common end plate is removably connected to said side face. The use of a common end plate makes it possible to maintain a large number of stacks.

[0031] According to one aspect, each stack interfaced with a lateral face is connected by independently of the common end plate associated with said side face. Thus, a single stack can be removed for maintenance, providing great flexibility.

[0032] According to one aspect, each stack interfaced with said lateral face comprises a personal end plate connected to the common end plate by a plurality of traction members. A single stack can be removed by removing its personal end plate.

[0033] According to one aspect, the first lateral face and the second lateral face are inclined relative to each other at a spacing angle such that the body of the collector is flared at the bottom. This facilitates the collection of water from the stacks in the collector while reducing its overall size.

[0034] A fuel cell is also presented comprising a collector as previously shown configured to be supplied by the air flow and the hydrogen flow and at least two stacks connected to the collector, each stack comprising a plurality of electrochemical cells.

[0035] According to one aspect, the maintenance process includes a step consisting of removing a common terminal plate from the collector body, the set of stacks fed from the side face associated with the common terminal plate remaining attached to the common terminal plate.

[0036] According to one aspect, the maintenance procedure comprises steps consisting of: • Remove a personal end plate from a stack, • Remove the stack from a common end plate, • Place a new stack on the common terminal plate, • Replace the personal terminal plate on the new stack. PRESENTATION OF THE FIGURES

[0037] The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0038] Fig. 1 is a schematic representation of an aircraft comprising electric propulsion motors powered by electrical power supply systems.

[0039] Fig. 2 is a schematic representation of an electrical power supply system according to the invention.

[0040] Fig. 3, Fig. 4 and Fig. 5 are respectively perspective, upstream and side views of an electrical power supply system according to one embodiment of the invention.

[0041] Figure 6 is a schematic representation of the fuel cell with a collector and stacks in assembled position.

[0042] Fig. 7 is a schematic representation of the fuel cell architecture.

[0043] Fig. 8 is a schematic representation of the fuel cell of Fig. 6 after the removal of a single stack.

[0044] Fig. 9 is a schematic representation of the fuel cell of Fig. 6 after the removal of a common terminal plate connected to several stacks.

[0045] It should be noted that the figures set out the invention in detail to implement the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0046] With reference to [Fig. 1], an aircraft A is shown comprising several electric propulsion motors M for its propulsion. The aircraft A further comprises two electrical power supply systems 1 according to the invention, each supplying power to several electric propulsion motors M.

[0047] It is understood that the invention applies to all types of aircraft, whether single-engine, twin-engine, or multi-engine. The invention relates to airplanes, helicopters, and vertical takeoff and landing aircraft.

[0048] In this example, the electric propulsion motors M are positioned in the immediate vicinity of the electrical power supply system 1 to which they are connected in order to limit electrical losses. It is understood that an electrical power supply system 1 could power only one electric propulsion motor M. In this example, the electrical power supply systems 1 are positioned under the lateral wings of the aircraft A, but it is understood that their positioning could be different.

[0049] With reference to [Fig. 3], an electrical power supply system 1 is shown according to one embodiment of the invention. The electrical power supply system 1 is mounted in an enclosure 10, also referred to as a "nacelle", extending along a longitudinal axis X oriented from upstream to downstream. In [Fig. 3], the enclosure 10 is open at the upstream end to accommodate one or more propulsion electric motors M (shown in [Fig. 3]).

[0050] In this example, with reference to Figures 3 to 5, the power supply system 1 comprises a single fuel cell 2 electrically powering a power distribution box 3 configured to be directly connected to the propulsion electric motors M. The power supply system 1 includes a support structure 15 having a lattice shape defining a main housing 16 in which the fuel cell 2 is mounted. The lattice structure comprises several tubes which are assembled to form meshes, in particular, rectangular in shape. Thus, the fuel cell 2 is protected from any mechanical shock, supported stably and adequately ventilated.

[0051] As is known, the fuel cell 2 generates electrical energy from an electrochemical reaction. Conventionally, different fluids circulate through the fuel cell 2 to react together and thus generate electrical energy. Such a reaction can notably be a redox reaction between dioxygen and dihydrogen. The fuel cell 2 is thus supplied with dioxygen and dihydrogen. The redox reaction also generates water, which is discharged from the fuel cell 2. In this example, with reference to [Fig. 2], as will be shown later, the electrical supply system 1 comprises an air supply circuit 7 to provide an air flow FA containing dioxygen to the fuel cell 2 and a hydrogen supply circuit 5 to provide a hydrogen flow FH to the fuel cell 2.

[0052] In this example, the fuel cell 2 is a high-temperature fuel cell in which the water generated by the reaction is in the vapor state. Indeed, water in the vapor state is easily discharged. It is understood that the invention also applies to a low-temperature fuel cell 2.

[0053] The fuel cell 2 is also supplied with coolant FR to dissipate the heat generated by the electrochemical reaction. Such coolant FR is a heat transfer fluid, such as oil or water, which may be mixed with additives. In this example, with reference to [Fig. 2], the power supply system 1 includes a cooling circuit 6, as will be shown later.

[0054] With reference to [Fig.2], the electrical power supply system 1 of [Fig.3] is schematically represented.

[0055] According to the invention, the fuel cell 2 comprises a first electrochemical line LA and a second electrochemical line LB electrically connected in parallel, each electrochemical line LA, LB comprising four independent stacks E1-E4, E5-E8 electrically connected in series as illustrated in [Fig.7].

[0056] The presence of at least two electrochemical lines LA, LB electrically connected in parallel advantageously allows them to be powered differently in order to natively regulate the power, that is, without using an electronic power regulation device. The presence of at least two independent stacks E1-E4, E5-E8, electrically connected in series, in an electrochemical line LA, LB advantageously allows for high electrical power while also enabling easy maintenance due to modularity.

[0057] This advantageously allows for optimal sizing of the com stack Fuel cell 2 is designed to provide a wide operating range without requiring a heavy and bulky electronic power regulation device. The modular structure of fuel cell 2 thus enables the formation of an electrical power system 1 with a high mass and volumetric power density, which is advantageous in an aeronautical context.

[0058] With reference to [Fig.6], the fuel cell 2 includes a collector 9 to which the stacks E1-E8 are connected. The collector 9 is supplied by the air flow FA and the hydrogen flow FH to supply each electrochemical line LA, LB.

[0059] With reference to [Fig. 6], the collector 9 extends longitudinally along a collector axis XC and vertically along a vertical axis Z. The collector 9 has a body 90 comprising a first lateral face Fl configured to interface with the stacks E1-E4 of the first electrochemical line LA and a second lateral face F2 configured to interface with the stacks E5-E8 of the second electrochemical line LB. In this example, with reference to [Fig. 6], the first lateral face Fl and the second lateral face F2 are inclined relative to each other at a spacing angle θ so that the collector 9 is flared at the bottom. Preferably, the fuel cell 2 has a V-shape. Preferably, the spacing angle θ is between 2° and 90°, preferably between 2° and 10°.This design advantageously allows for the gravity collection of residues from the electrochemical reactions of the E1-E8 stacks, such as water, in collector 9, while maintaining a compact footprint. This architecture also improves structural integrity. Using a collector 9 enables the use of several low-height E1-E8 stacks in the same electrochemical line. The offset mass, i.e., the mass of the cantilevered E1-E8 stacks, is therefore reduced, thus limiting high-frequency vibrational modes.

[0060] The manifold 9 further includes a connection face F3 which is preferably located downstream in order to connect to the air supply circuit 7 and the hydrogen supply circuit 5. As illustrated in [Fig.6], the connection face F3 includes a hydrogen inlet connector 91a configured to supply all stacks E1-E8, a hydrogen outlet connector 91b, an air inlet connector 92a configured to supply stacks E1-E8 and an air outlet connector 92b.

[0061] Alternatively, the connecting face F3 could comprise: • a first hydrogen connector configured to power the E1-E4 stacks on the first side face Fl, • a second hydrogen connector configured to power the E5-E8 stacks on the second side face F2, • a first air connector configured to supply the E1-E4 stacks of the first side face Fl and • a second air connector configured to supply the E5-E8 stacks of the second side face F2.

[0062] According to this aspect, each electrochemical line LA, LB is supplied independently with air flow FA and hydrogen flow FH. The manifold 9 advantageously includes independent internal conduits to supply each electrochemical line LA, LB.

[0063] Preferably, the power supply system 1 includes an air regulating valve (not shown), preferably associated with each electrochemical line LA, LB, so as to regulate the power in the fuel cell 2 without resorting to an electronic power regulation device.

[0064] Preferably, the power supply system 1 includes a hydrogen regulating valve (not shown), preferably associated with each electrochemical line LA, LB, so as to regulate the power in the fuel cell 2 without resorting to an electronic power regulation device.

[0065] Preferably, and again with reference to [Fig.6], the hydrogen connectors 91a, 91b are located vertically above the air connectors 92a, 92b so as to segregate as much as possible the hydrogen flow FH in the upper part and the air flow FA in the lower part of the power supply system 1. Since hydrogen is lighter than air, the hydrogen is separated from the air in the event of a leak, which allows for appropriate treatment.

[0066] As illustrated in Figures 6, 8 and 9, the fuel cell 2 has a modular structure to facilitate its maintenance.

[0067] In this example, the first side face Fl is connected to a first common terminal plate 22a to which are connected all the stacks E1-E4 powered by said first side face Fl, that is to say, the stacks E1-E4 of the first electrochemical line LA. Similarly, the second side face F2 is connected to a second common terminal plate 22b to which are connected all the stacks E5-E8 powered by said second side face F2, that is to say, the stacks E5-E8 of the second electrochemical line LB.

[0068] Preferably, each common end plate 22a, 22b has supply openings for each stack E1-E8. Advantageously, a flat sealing gasket can be used with each common end plate 22a, 22b, which improves leak tightness compared to a hydraulic / pneumatic connection. Advantageously, since each common end plate 22a, 22b is supported against the body 90 of the manifold 9, each common end plate 22a, 22b can intrinsically possess a mass and a volume smaller than a traditional terminal plate since it can benefit from the rigidity of the body 90 of the collector 9 to which it is connected.

[0069] As illustrated in [Fig. 6], each common terminal plate 22a, 22b is removably connected to a lateral face Fl, F2 of the collector body 90, in particular, by means of connecting elements 23 such as screws or the like. This advantageously allows an entire electrochemical line LA, LB to be removed from the fuel cell 2 by simply removing a common terminal plate 22a, 22b, as will be shown later.

[0070] Each stack E1-E4 supplied by said first lateral face Fl is independently connected to the first common end plate 22a. Similarly, each stack E5-E8 supplied by said second lateral face F2 is independently connected to the second common end plate 22b. In this example, as illustrated in [Fig. 6], each stack E1-E8 is held between a personal end plate 20 and a common end plate 22a, 22b by a plurality of tensioning members 21 called "tie rods." A tensioning member 21 is, for example, in the form of a threaded rod. In this example, the tensioning members 21 are connected to the personal end plate 20 by fastening members 24, for example, nuts.

[0071] This allows the removal of a stack E1-E8 by removing the personal end plate 20 of said stack E1-E8, the common end plate 22a, 22b not being removed, and thus ensuring continued airtight compression of the other stacks. Preferably, the plurality of traction members 21 are integral with the common end plate 22a, 22b. Therefore, only one operator needs to act on the accessible fastening members 24 to perform a removal.

[0072] With reference to [Fig. 8], an example of implementing a method for dismantling a single stack E4 will be presented. The method includes a step of removing the personal end plate 20 retaining said stack E4 so as to allow its removal. In practice, it is sufficient to remove the fastening members 24 associated with the personal end plate 20 to release the stack E4. The stack E4 can be moved away from the manifold 9 and its lateral face FL. A new stack can then be put in place conveniently and quickly without affecting the sealing of the other stacks, which is very advantageous. The personal end plate 20 is then put in place and locked in position by the fastening members 24 mounted on the traction members 21.

[0073] With reference to [Fig. 9], an example of implementing a method for dismantling all the E1-E4 stacks of the first electrochemical line LA will be presented. The dismantling method includes a step consisting of removing the first common end plate 22a by removing the connecting members 23. As the stacks E1-E4 are held between the first common terminal plate 22a and their personal terminal plates 20, these can be handled together.

[0074] This allows for a quick removal in order to replace the E1-E4 stacks without individually removing each personal terminal plate 20. A new common first terminal plate associated with several new stacks can then be put in place conveniently and quickly.

[0075] With reference to [Fig.3], the electrical distribution box 3 is electrically connected to the fuel cell 2. In this example, the electrical distribution box 3 has a plurality of electrical connectors 30 for directly connecting propulsion electric motors M.

[0076] According to a preferred aspect of the invention, the electrical distribution box 3 is free of electronic power regulation devices. Thus, it lacks power components such as converters, particularly direct current (DC / DC) converters, necessary for adapting the power supplied to the propulsion electric motors M, as in the prior art. Preferably, the electrical distribution box 3 is free of electric batteries.

[0077] With reference to [Fig. 6], as previously shown, the fuel cell 2 includes air connectors 92a, 92b in its lower part and hydrogen connectors 91a, 91b in its upper part. This advantageously allows for the segregation of air and hydrogen within the enclosure 10. As illustrated in Figures 3 to 4, the air supply circuit 7 is positioned in a lower part of the enclosure 10, while the hydrogen supply circuit 5 is positioned in an upper part of the enclosure 10 to increase segregation. Similarly, the cooling circuit 6 is positioned in a lower part of the enclosure 10.

[0078] As previously described, the air connectors 92a, 92b and the hydrogen connectors 91a, 91b are positioned at the downstream end of the fuel cell 2, while the electrical distribution box 3 is mounted upstream of the fuel cell 2, specifically upstream of the main housing 16. This allows the fuel supply to be separated from the electrical equipment to reduce the risk of accidents. The electrical components related to the air supply circuit 7 and the cooling circuit 6 (including pumps) are also mounted upstream of the fuel cell 2. This creates a separation within the enclosure between the electrical components and the fuels, thereby improving safety.

[0079] The hydrogen connectors 91a, 91b are positioned at the top of the downstream end so that the hydrogen supply circuit 5 has a reduced length. Such a hydrogen supply circuit 5 is expensive because it requires a high degree of safety.

[0080] Furthermore, the use of common terminal plates 22a, 22b and a collector 9 makes it possible to reduce the hydrogen leakage paths (two paths for the common terminal plates 22a, 22b and two paths for the hydrogen connectors 91a, 91b) for 8 stacks E1-E8, which is low compared to the prior art which imposed two leakage paths per stack (one terminal plate and one hydrogen connector).

[0081] With reference to [Fig. 2], the cooling circuit 6 is configured to circulate a coolant FR within the fuel cell 2, in particular, in a closed loop. The cooling circuit 6 includes a cooling circulation pump 60 for driving the coolant FR. In this example, the cooling circulation pump 60 is positioned vertically below the fuel cell 2 so as to keep it away from the hydrogen supply circuit 5, which is supplied from above.

[0082] In this example, with reference to [Fig. 2], the cooling circuit 6 includes a heat exchanger 61 to remove the heat collected by the cooling fluid FR in the fuel cell 2. As illustrated in [Fig. 4], the enclosure 10 has an auxiliary air inlet 13 to allow the admission of a cooling airflow FAR intended to collect heat from the heat exchanger 61. Preferably, the enclosure 10 has two auxiliary air inlets 13 positioned on opposite side walls of the enclosure 10.

[0083] With reference to [Fig. 2], the air supply circuit 7 is configured to supply the fuel cell 2 with an airflow FA. The air supply circuit 7 includes an upstream air inlet 11 formed in the enclosure 10. The air supply circuit 7 includes an air circulation pump 70 for compressing the airflow FA to a pressure compatible with the fuel cell 2. In this example, the air circulation pump 70 is positioned vertically below the fuel cell 2 so as to keep it away from the hydrogen supply circuit 5, which is supplied from above.

[0084] With reference to [Fig.2], the power supply system 1 further includes an auxiliary power box 8 configured to electrically supply the air circulation pump 70 and the cooling circulation pump 60. The auxiliary power box 8 is electrically supplied by the power distribution box 3 or by the fuel cell 2.

[0085] An example of the implementation of a method for supplying power to several propulsion electric motors M connected directly to the electrical distribution box 3 of an electrical power supply system 1.

[0086] The method of use includes a step of supplying each amission line LA, LB of the fuel cell 2 with an air flow FA and with a flow of hydrogen FH. The air flow FA is routed from a lower part of the enclosure 10 while the hydrogen flow FH is routed from an upper part of the enclosure 10. Each electrochemical line LA, LB is supplied independently and regulated with air flow FA and hydrogen flow FH to provide power adapted to the flight phase of the electric propulsion motors M.

[0087] The electrical distribution box 3 collects power from each electrochemical line LA, LB to directly power the propulsion electric motors M, i.e., without the need for an electronic power regulation device. Advantageously, the auxiliary electrical box 8 draws power from the electrical distribution box 3 to power the pumps 60, 70 of the cooling circuit 6 and the air supply circuit 7.

Claims

Claims

1. Electrical power supply system (1) for at least one electric propulsion engine (M) of an aircraft (A), the electrical power supply system (1) comprising a fuel cell (2), configured to be powered by an air flow (FA) and by a hydrogen flow (FH), configured to electrically power an electrical distribution box (3) configured to be connected to said electric propulsion engine (M), system characterized in that the fuel cell (2) comprises at least a first electrochemical line (LA) and a second electrochemical line (LB) electrically mounted in parallel, each electrochemical line (LA, LB) comprising at least two independent stacks (E1-E8) electrically mounted in series, each stack (E1-E8) comprising a plurality of electrochemical cells.

2. A power supply system (1) according to claim 1, wherein the power distribution box (3) is free from a power regulation device.

3. Electrical power supply system (1) according to one of claims 1 to 2, comprising an air supply circuit (7) configured to supply the fuel cell (2) with an air flow (FA), the air supply circuit (7) comprising an upstream air inlet (11).

4. An electrical power supply system (1) according to claim 3, wherein the electrical distribution box (3) is positioned upstream of the fuel cell (2).

5. Power supply system (1) according to one of claims 3 and 4, wherein the air supply circuit (7) comprises an air circulation pump (70) positioned vertically under the fuel cell (2).

6. Power supply system (1) according to one of claims 1 to 5, wherein the fuel cell (2) comprises an upper part comprising at least one hydrogen connector (91a, 91b) and a lower part comprising at least one air connector (92a, 92b).

7. An electrical power system (1) according to one of claims 1 and 6, comprising a support structure (15) having a lattice shape defining a main housing (16) in which the fuel cell (2) is mounted.

8. Power supply system (1) according to one of claims 1 to 7, wherein the fuel cell (2) comprises a collector (9)

9.

10.

11.

12.

13. configured to be supplied by the air flow (FA) and by the hydrogen flow (FH), the collector (9) being connected to the two electrochemical lines (LA, LB). Electrical power supply system (1) according to one of claims 1 to 8, wherein each electrochemical line (LA, LB) is configured to be powered independently. Assembly formed from a power supply system according to one of claims 1 to 9 and at least one aircraft propulsion electric motor (M) connected to the electrical distribution box (3). Assembly according to claim 10, in which the aircraft propulsion electric motor (M) is connected directly to the electrical distribution box (3). Aircraft (A) comprising at least one assembly according to one of claims 10 and 11 to enable the propulsion of said aircraft (A). Method for electrically supplying (1) at least one electric propulsion motor (M) of an aircraft (A) connected to an electrical supply system (1) according to one of claims 1 to 9, the method comprising steps consisting of: • Power the fuel cell (2) with an air flow (FA) and a hydrogen flow (FH) to electrically power the electrical distribution box (3) connected to said electric propulsion motor (M), and • Regulate at least the air flow (FA) in each electrochemical line (LA, LB) so as to regulate the electrical power supplied by the fuel cell (2).

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