System for supplying electrical power to an aircraft-propelling electric motor comprising a fuel cell

Abstract

The invention relates to a system (1) for supplying electrical power to at least one aircraft-propelling electric motor (M), the system (1) for supplying electrical power comprising a fuel cell (2), which is configured to be fed with a flow of air (FA) and with a flow of hydrogen (FH) and configured to supply electric power to an electrical distribution unit (3) that is configured to be connected to said propelling electric motor (M), the fuel cell (2) comprising at least a first electrochemical line (LA) and a second electrochemical line (LB) that are mounted electrically in parallel, each electrochemical line (LA, LB) comprising at least two independent stacks (E1-E8) mounted electrically in series, each stack (E1-E8) comprising a plurality of electrochemical cells.

Description

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

[0001] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various carbon emission restrictions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new aircraft types and those already in operation, requiring the implementation of technological solutions to ensure their compliance with current regulations. Civil aviation has been mobilizing 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 consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products 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 and minimizing 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, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to ensure propulsion, and, as an essential complement to technological progress, aeronautical biofuels.

[0005] It has thus been proposed to equip an aircraft with a plurality of electric propulsion motors in order to enable the propulsion of the aircraft. In a known manner, the aircraft comprises at least one fuel cell to electrically power a plurality of electric propulsion motors. In practice, depending on the flight phase of the aircraft (takeoff, cruise, taxi, etc.), the power required by the electric propulsion motors is different, which translates, for the fuel cell, as a variable electrical load. To enable the supply of a variable electrical load, it is known to use several fuel cells associated with an electronic power regulation device in order to meet the needs of the aircraft while maintaining the fuel cells in a high-efficiency operating range.The integration of an electronic power control device significantly increases the volume and mass, which is particularly penalizing in an aeronautical context. In practice, it is complex to obtain fuel cells that exactly meet the needs and oversized fuel cells are generally used, which penalizes the 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 electric propulsion engine of an aircraft, the electrical power supply system comprising a fuel cell, configured to be powered by a flow of air and by a flow of hydrogen, configured to electrically power an electrical distribution box configured to be connected to said electric propulsion engine.

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

[0009] The invention provides great flexibility in the choice of stacks and avoids the need for a fuel cell comprising a single stack with oversized power, which penalizes mass and size. The modular design of the fuel cell also ensures precise positioning of the center of gravity in order to gain stability and optimize size. The use of several independent stacks facilitates maintenance while allowing high voltage levels to be achieved.

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

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

[0012] Preferably, the fuel cell comprises only a first electrochemical line and a second electrochemical line electrically connected in parallel. This provides flexibility as well as redundancy.

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

[0014] In one aspect, the electrical power 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 flows from upstream to downstream. The terms upstream and downstream are defined with respect to the direction of travel of the aircraft which is moving upstream.

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

[0016] In 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 portion comprising at least one hydrogen connector and a lower portion comprising at least one air connector. This makes it possible to optimize the size while allowing segregation into air (in the lower portion) and hydrogen (in the upper portion) by taking advantage of the fact that air is heavier than hydrogen.

[0018] In one aspect, the power supply system includes 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 from shock.

[0019] In 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] In one aspect, the fuel cell includes a collector configured to be powered by the air flow and the hydrogen flow, the collector being connected to both 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. The collector also reduces the number and size of possible hydrogen leakage paths. The stacks can also be optimally tilted during operation.

[0022] In one aspect, each electrochemical line is configured to be powered independently. Thus, the power generated by each electrochemical line can be independently regulated.

[0023] The invention also relates to an assembly formed from a power supply system, as presented previously, and at least one aircraft propulsion electric motor connected to the electrical distribution box. According to one aspect, the aircraft propulsion electric motor is connected directly to the electrical distribution box. It is thus not necessary to use an electronic power regulation device.

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

[0025] The invention also relates to a method for electrically powering at least one aircraft electric propulsion motor connected to an electrical power supply system, as presented previously, the method comprising steps consisting of:Powering the fuel cell with a flow of air and with a flow of hydrogen to electrically power the electrical distribution box connected to said electric propulsion motor, andRegulating at least the flow of air in each electrochemical line so as to regulate the electrical power supplied by the fuel cell.

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

[0027] Such a collector allows several stacks to be spatially distributed in order to increase compactness and reduce space requirements.

[0028] In one aspect, the hydrogen connectors are located vertically above the air connectors. This helps prevent fluid mixing and facilitates the treatment of any leaks.

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

[0030] In one aspect, the common end plate is removably connected to said side face. The use of a common end plate allows maintenance of a large quantity of stacks.

[0031] In one aspect, each stack interfaced with a side face is independently connected to the common end plate associated with said side face. Thus, a single stack can be removed in the event of maintenance, which provides great flexibility.

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

[0033] In one aspect, the first side face and the second side face are inclined relative to each other at a spacing angle such that the body of the collector is flared at the bottom. This makes it easier to collect water from the stacks in the collector while reducing the footprint.

[0034] Also disclosed is a fuel cell comprising a collector as previously disclosed configured to be powered 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 method comprises a step of removing a common end plate from the collector body, the set of stacks supplied by the side face associated with the common end plate remaining secured to the common end plate.

[0036] In one aspect, the maintenance method includes steps of:Removing a personal endplate from a stack,Removing the stack from a common endplate,Posting a new stack on the common endplate,Posting the personal endplate back on the new stack. PRESENTATION OF 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] This is a schematic representation of an aircraft incorporating electric propulsion motors powered by electrical power systems.

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

[0040] La, laand laare respectively perspective views, from upstream and from the side of an electrical power supply system according to one embodiment of the invention.

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

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

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

[0044] This is a schematic representation of the fuel cell after removal of a common end plate connected to multiple stacks.

[0045] It should be noted that the figures set out the invention in detail to implement the invention, said figures can of course be used to better define the invention if necessary. DETAILED DESCRIPTION OF THE INVENTION

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

[0047] It goes without saying that the invention applies to any type of aircraft, with a single engine, with two engines, with a large number of distributed engines. The invention concerns airplanes, helicopters or aircraft with vertical landing and takeoff.

[0048] In this example, the electric propulsion motors M are positioned in the immediate vicinity of the electrical power supply system 1 with which they are associated in order to limit electrical losses. It goes without saying that an electrical power supply system 1 could only power a single 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 goes without saying that their positioning could be different.

[0049] With reference to the, there is shown an electrical power supply system 1 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 the, the enclosure 10 is open upstream in order to receive one or more electric propulsion motors M (shown in the).

[0050] In this example, with reference to Figures 3 to 5, the electrical power system 1 comprises a single fuel cell 2 electrically powering an electrical distribution box 3 configured to be directly connected to the propulsion electric motors M. The electrical power system 1 comprises 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, of rectangular shape. Thus, the fuel cell 2 is protected from any mechanical shock, supported in a stable manner and sufficiently ventilated.

[0051] In a known manner, the fuel cell 2 makes it possible to generate electrical energy from an electrochemical reaction. Conventionally, different fluids circulate through the fuel cell 2 in order to react together and thus generate electrical energy. Such a reaction may in particular be an oxidation-reduction reaction between dioxygen and dihydrogen. The fuel cell 2 is thus supplied with dioxygen and dihydrogen. The oxidation-reduction reaction also generates water which is discharged from the fuel cell 2. In this example, with reference to the, as will be presented subsequently, the electrical power supply system 1 comprises an air supply circuit 7 for supplying an air flow FA comprising dioxygen to the fuel cell 2 and a hydrogen supply circuit 5 for supplying a hydrogen flow FH to the fuel cell 2.

[0052] In this example, the fuel cell 2 is a high-temperature cell in which the water generated by the reaction is in the vapor state. Indeed, water in the vapor state is easily evacuated. It goes without saying that the invention also applies to a low-temperature fuel cell 2.

[0053] The fuel cell 2 is also supplied with cooling fluid FR in order to remove the heat generated by the electrochemical reaction. Such a cooling fluid FR is a heat transfer fluid, such as oil or water which can be mixed with additives. In this example, with reference to the, the electrical power system 1 comprises a cooling circuit 6 as will be presented later.

[0054] With reference to the, the power supply system 1 of the is shown schematically.

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

[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 regulate the power natively, that is to say, 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 high electrical power to be available while allowing easy maintenance due to the modularity.

[0057] This advantageously makes it possible to optimally size the fuel cell 2 in order to have a wide operating range without requiring an electronic power regulation device which is heavy and bulky. The modular structure of the fuel cell 2 thus makes it possible to form an electrical power supply system 1 having a high mass and volume power density, which is advantageous in an aeronautical context.

[0058] With reference to the, the fuel cell 2 comprises 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 1a, 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 F1 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 1a, the first lateral face F1 and the second lateral face F2 are inclined relative to each other by a spacing angle θ so that the collector 9 is flared in the lower part. 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 advantageously allows the residues from the electrochemical reactions of the E1-E8 stacks, for example, water, to be recovered by gravity in the collector 9, while having a limited footprint. Such an architecture also makes it possible to improve the structural strength. The use of a collector 9 makes it possible to use 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 lower, which limits the natural modes in high-frequency vibration.

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

[0061] Alternatively, the connection face F3 could comprise: a first hydrogen connector configured to supply the stacks E1-E4 of the first lateral face F1, a second hydrogen connector configured to supply the stacks E5-E8 of the second lateral face F2, a first air connector configured to supply the stacks E1-E4 of the first lateral face F1 and a second air connector configured to supply the stacks E5-E8 of the second lateral face F2.

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

[0063] Preferably, the electrical power supply system 1 comprises an air control 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 control device.

[0064] More preferably, the electrical power supply system 1 comprises a hydrogen regulation 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, still with reference to the, 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 electrical supply system 1. As hydrogen is lighter than air, the hydrogen is separated from the air in the event of a leak, which allows suitable 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 lateral face F1 is connected to a first common terminal plate 22a to which all of the stacks E1-E4 supplied by said first lateral face F1 are connected, i.e., the stacks E1-E4 of the first electrochemical line LA. Similarly, the second lateral face F2 is connected to a second common terminal plate 22b to which all of the stacks E5-E8 supplied by said second lateral face F2 are connected, i.e., the stacks E5-E8 of the second electrochemical line LB.

[0068] Preferably, each common end plate 22a, 22b has feed openings for each stack E1-E8. Advantageously, a planar seal may 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 bears against the body 90 of the manifold 9, each common end plate 22a, 22b may inherently have a smaller mass and volume than a traditional end plate since it can benefit from the rigidity of the body 90 of the manifold 9 to which it is connected.

[0069] As illustrated in , each common end plate 22a, 22b is removably connected to a lateral face F1, F2 of the body 90 of the collector 9, in particular, by connecting members 23 such as screws or the like. This advantageously makes it possible to remove an entire electrochemical line LA, LB from the fuel cell 2 by simply dismantling a common end plate 22a, 22b as will be presented later.

[0070] Each stack E1-E4 supplied by said first lateral face F1 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 , each stack E1-E8 is held between a personal end plate 20 and a common end plate 22a, 22b by a plurality of traction members 21 called “tie rods”. A traction member 21 is for example in the form of a threaded rod. In this example, the traction members 21 are connected to the personal end plate 20 by fixing members 24, for example, nuts.

[0071] This makes it possible to remove a stack E1-E8 by removing the personal end plate 20 from said stack E1-E8, the common end plate 22a, 22b not being removed and making it possible to continue to ensure the sealed compression of the other stacks. Preferably, the plurality of traction members 21 is integral with the common end plate 22a, 22b. Thus, it is sufficient for an operator to act only on the fixing members 24 which are accessible to carry out a removal.

[0072] With reference to the, an example of implementation of a method for dismantling a single stack E4 will be presented. The method comprises a step consisting 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 fixing members 24 associated with the personal end plate 20 to release the stack E4. The stack E4 can be translated away from the collector 9 and its lateral face F1. A new stack can then be put in place in a practical and rapid manner 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 fixing members 24 mounted on the traction members 21.

[0073] With reference to the, an example of implementation of a method for dismantling all of the stacks E1-E4 of the first electrochemical line LA will be presented. The dismantling method comprises 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 end plate 22a and their personal end plates 20, they can be handled together.

[0074] This allows for rapid removal to replace the E1-E4 stacks without individually removing each personal end plate 20. A new first common end plate associated with several new stacks can then be conveniently and quickly installed.

[0075] With reference to the, the electrical distribution box 3 is electrically connected to the fuel cell 2. In this example, the electrical distribution box 3 comprises 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 is free of power components such as converters, in particular 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, as presented previously, the fuel cell 2 comprises in a lower part air connectors 92a, 92b and in an upper part hydrogen connectors 91a, 91b. This advantageously makes it possible to segregate the air and hydrogen in the enclosure 10. As illustrated in FIGS. 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 in order to increase the segregation. Similarly, the cooling circuit 6 is positioned in a lower part of the enclosure 10.

[0078] As presented previously, 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, in particular, upstream of the main housing 16. This makes it possible to separate the fuel supply from the electrical equipment to reduce the risk of accidents. The electrical components linked to the air supply circuit 7 and to the cooling circuit 6 (pumps in particular) are also mounted upstream of the fuel cell 2. Thus, segregation is achieved in the enclosure between the electrical components and the fuels, which improves safety.

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

[0080] In addition, the use of common end plates 22a, 22b and a collector 9 makes it possible to reduce the hydrogen leakage paths (two paths for the common end 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 end plate and one hydrogen connector).

[0081] With reference to the, the cooling circuit 6 is configured to circulate a cooling fluid FR in the fuel cell 2, in particular, in a closed loop. The cooling circuit 6 comprises a cooling circulation pump 60 for driving the cooling fluid FR. In this example, the cooling circulation pump 60 is positioned vertically under the fuel cell 2 so as to separate it from the hydrogen supply circuit 5 which is routed from an upper part.

[0082] In this example, with reference to the, the cooling circuit 6 comprises a heat exchanger 61 for evacuating the calories collected by the cooling fluid FR in the fuel cell 2. As illustrated in the, the enclosure 10 comprises an auxiliary air inlet orifice 13 to allow the admission of a cooling air flow FAR intended to collect calories from the heat exchanger 61. Preferably, the enclosure 10 comprises two auxiliary air inlet orifices 13 positioned on opposite side walls of the enclosure 10.

[0083] With reference to the, the air supply circuit 7 is configured to supply the fuel cell 2 with an air flow FA. The air supply circuit 7 comprises an upstream air inlet 11 formed in the enclosure 10. The air supply circuit 7 comprises an air circulation pump 70 for compressing the air flow FA to a pressure compatible with the fuel cell 2. In this example, the air circulation pump 70 is positioned vertically under the fuel cell 2 so as to separate it from the hydrogen supply circuit 5 which is routed from an upper portion.

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

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

[0086] The method of use comprises a step of supplying each intake line LA, LB of the fuel cell 2 with an air flow FA and a hydrogen flow FH. The air flow FA is conveyed from a lower part of the enclosure 10 while the hydrogen flow FH is conveyed via 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 the power on each electrochemical line LA, LB to directly power the propulsion electric motors M, that is to say, without resorting to an electronic power regulation device. Advantageously, the auxiliary electrical box 8 takes power from the electrical distribution box 3 to power the pumps 60, 70 of the cooling circuit 6 and of the air supply circuit 7.

Claims

Electrical power supply system (1) for at least one electric propulsion engine (M) of an aircraft (A), the electrical power supply system (1) extending from upstream to downstream along a longitudinal axis (X), 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), the fuel cell (2) comprising 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, the fuel cell (2) comprising a collector (9) configured to be powered by the air flow (FA) and by the hydrogen flow (FH), the collector (9) being connected to the two electrochemical lines (LA, LB),the fuel cell (2) comprising air connectors (92a, 92b) and hydrogen connectors (91a, 91b) positioned at a downstream end of the fuel cell (2), 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), an electrical distribution box (3) configured to be connected to said electric propulsion motor (M), the electrical distribution box (3) being electrically powered by the fuel cell (2) and positioned upstream of said fuel cell (2)., Power supply system (1) according to claim 1, wherein the power distribution box (3) is free from a power regulation device. Power supply system (1) according to one of claims 1 to 2, wherein the air supply circuit (7) comprises an air circulation pump (70) positioned vertically under the fuel cell (2). Power supply system (1) according to one of claims 1 to 3, wherein the fuel cell (2) comprises an upper part comprising the hydrogen connectors (91a, 91b) and a lower part comprising the air connectors (92a, 92b). Electrical power system (1) according to one of claims 1 and 4, comprising a support structure (15) having a lattice shape defining a main housing (16) in which the fuel cell (2) is mounted. Electrical power supply system (1) according to one of claims 1 to 5, 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 6 and at least one aircraft propulsion electric motor (M) connected to the electrical distribution box (3). Assembly according to claim 7, in which the aircraft propulsion electric motor (M) is connected directly to the electrical distribution box (3). Aircraft nacelle comprising at least one assembly according to one of claims 7 and 8 to enable the propulsion of said aircraft (A). Aircraft (A) comprising at least one assembly according to one of claims 7 and 8 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 6, the method comprising steps consisting of: Supplying the fuel cell (2) with an air flow (FA) and with a hydrogen flow (FH) to electrically supply the electrical distribution box (3) connected to said electric propulsion motor (M), and Regulating 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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