Framework for a fuel cell membrane-electrode assembly, membrane-electrode assembly, stack, fuel cell and associated vehicle

Abstract

Frame for a membrane-electrode assembly of a fuel cell, membrane-electrode assembly, stack, fuel cell and associated vehicle The present invention relates to a peripheral frame (76) for a membrane-electrode assembly (50). The frame comprises pairs of frame ports (59a, 59b, 59c), each pair of frame ports consisting of a single frame inlet port (51a, 51b, 51c) and a single frame outlet port (53a, 53b, 53c) for the circulation of a given functional fluid. The frame inlet port and the frame outlet port are arranged symmetrically opposite each other. One pair of frame ports (59a) is a pair of frame ports symmetrical with respect to a central frame axis (A50), and another pair of frame ports (59b, 59c) is a pair of frame ports asymmetrical with respect to the central frame axis (A50). (See Figure 3 for abbreviations.)

Description

Title of the invention: Frame for a membrane-electrode assembly of a fuel cell, membrane-electrode assembly, stack, fuel cell and associated vehicle

[0001] The present invention relates to a frame for a membrane-electrode assembly of a fuel cell, a membrane-electrode assembly, a stack, as well as an associated fuel cell and vehicle.

[0002] In the field of fuel cells, it is known to seek to make the flow of reactive gas and / or coolant uniform, while optimizing the amount of reactive gas consumed, so that the fuel cell cells operate uniformly and optimally. To this end, US10923740B2 describes the use of cathode and anode plates forming bipolar plates and membrane-electrode assemblies with fluid supply and discharge ports that form fluid supply and discharge galleries. More specifically, the anode and cathode plates and the membrane-electrode assemblies comprise one supply port for each reactive gas, two coolant supply ports, two discharge ports for each reactive gas, and two discharge ports for the coolant, arranged on either side of the anode and cathode plates and the membrane-electrode assemblies.The orifices through which the reactive gases flow are asymmetrical with respect to the center of the separator plates and the membrane-electrode assemblies respectively, while the orifices through which the refrigerant flows are symmetrical with respect to the center of the plates and the membrane-electrode assemblies respectively.

[0003] However, these provisions dictate the geometry of the orifices of the bipolar plates, in other words, the shape of these orifices, as well as the orientation of the bipolar plates relative to each other. Indeed, the bipolar plates must all be oriented in the same direction in order to define supply and discharge galleries with an optimized cross-section.

[0004] The object of the invention is to resolve the disadvantages of the prior art by proposing a new stacking for a fuel cell that allows for the optimization of fluid flow in a simple way without imposing a geometry of the orifices of the bipolar plates or a particular orientation of the bipolar plates.

[0005] For this purpose, the invention relates to a peripheral frame for a membrane-electrode assembly of a fuel cell, the frame extending parallel to a frame plane.

[0006] According to the invention, the frame comprises pairs of frame ports, each pair of frame ports being made up of a single frame supply port and a single frame discharge port for the circulation of the same given functional fluid, which is different from the fluid circulating in any other pair of frame ports of the peripheral frame, the frame supply port and the frame discharge port being arranged symmetrically opposite each other with respect to a central frame axis perpendicular to the frame plane and passing through a frame center,

[0007] one of the pairs of frame holes is a symmetrical pair of frame holes in that the two frame holes of the pair of frame holes are symmetrical with respect to the central frame axis,

[0008] Another pair of frame ports is an asymmetrical pair of frame ports in that the two frame ports of the asymmetrical pair of frame ports are asymmetrical with respect to the central frame axis.

[0009] One idea underlying the invention is to provide that each functional fluid flows through only one supply port and one discharge port, and that the peripheral frame of the membrane-electrode assembly has a pair of ports asymmetrical with respect to a central axis of the frame, parallel to the stacking direction and passing through the center of the frame, and a pair of ports symmetrical with respect to the central axis of the frame. The fluid flow through the pair of asymmetric ports is thus optimized between the supply and discharge ports. For example, such asymmetry makes it possible to manage and generate different fluid flow patterns through the supply and discharge ports. This allows, for example, for compensating for certain pressure losses or limiting them.In practice, since it is not necessary to optimize the geometry of the orifices to optimize the flow of all fluids circulating through the orifices, the functional fluid whose flow does not need to be optimized circulates through the pair of symmetrical frame orifices, which simplifies the manufacture of the frame by limiting the number of asymmetrical orifices in the frame.

[0010] According to other advantageous aspects of the invention, the frame comprises one or more of the following features, taken individually or in all technically possible combinations:

[0011] - each frame opening delimits a section, parallel to the frame plane, and for the pair of asymmetrical frame ports, an area of ​​the cross-section of the frame feed port is less than an area of ​​the cross-section of the frame discharge port, advantageously by a factor between 5% and 50%, preferably between 8% and 33%;

[0012] - each frame opening is delimited by a respective peripheral edge, and for the pair of asymmetrical frame holes: - the peripheral edge of the frame feed opening includes an overlapping portion and an overhanging portion; - the peripheral edge of the frame drain hole comprises an overlapping portion and a recessed portion; - the superimposed portion of the frame feed opening is identical in shape to the superimposed portion of the frame discharge opening; and - the overhanging portion is more offset towards the inside of the frame feed opening than the recessed portion is towards the inside of the frame discharge opening;

[0013] - the superimposed portion of the frame feed orifice is disposed between the overhanging portion and a central opening in the frame;

[0014] - for the pair of asymmetrical frame ports: - the peripheral edge of the frame drain hole forms corners; - the peripheral edge of the frame feed opening forms corners; - the recessed portion forms at least one of the corners of the peripheral edge of the frame drain hole; and - none of the corners of the peripheral edge of the frame feed hole are formed by the overhanging portion.

[0015] The invention also relates to a membrane electrode assembly comprising: - a membrane; and - a frame as defined previously, the membrane extending parallel to the plane of the frame and the frame surrounding the membrane.

[0016] The invention also relates to a stack for a fuel cell, the stack comprising: - a separator plate, extending perpendicularly to a stacking direction, the separator plate comprising: • a circulation field, and • a peripheral zone surrounding the circulation field and comprising two pairs of plate ports, each pair of plate ports comprising a plate feed port and a plate discharge port, fluidically connected by the circulation field, such that for each pair of plate ports, a functional fluid flowing through the plate feed port also flows through the plate discharge port; and - a membrane-electrode assembly as defined previously, superimposed on the separating plate,

[0017] the frame inlet and outlet ports of the same pair of frame ports being respectively superimposed on the plate inlet and outlet ports of the same pair of plate ports, such that the given functional fluid flowing through the frame inlet and outlet ports belonging to the same pair of frame ports also flows through the superimposed plate inlet and outlet ports belonging to the same pair of plate ports,

[0018] the plate and frame superimposed supply ports forming respectively part of two supply galleries parallel to the stacking direction and the plate and frame superimposed discharge ports forming part of two discharge galleries, parallel to the stacking direction, so that one of the given functional fluids circulates in a single supply gallery, supplies the circulation field, and is discharged through a single discharge gallery.

[0019] According to other advantageous aspects of the invention, the stack comprises several membrane-electrode assemblies, and several separator plates, superimposed alternately in the stacking direction.

[0020] The invention also relates to a fuel cell comprising:

[0021] - a stacking as defined above; and

[0022] - two supply lines for a given respective functional fluid, each a conduit being connected to a single supply gallery to supply that supply gallery with respective functional fluid, and two discharge conduits, each connected to a single discharge gallery to discharge the respective functional fluid from the discharge gallery.

[0023] According to other advantageous aspects of the invention, the fuel cell comprises one or more of the following features, taken individually or in any technically possible combination:

[0024] - one of the functional fluids is hydrogen, and the supply line in hydrogen and the hydrogen discharge line are connected respectively to the supply gallery and the discharge gallery formed in part from symmetrical pairs of frame ports;

[0025] - one of the functional fluids is oxygen, and the supply line to oxygen and oxygen exhaust line are connected respectively to the supply gallery and the exhaust gallery formed in part from pairs of asymmetrical frame ports;

[0026] - one of the functional fluids is a cooling fluid, and the pipe cooling fluid supply and fluid discharge line Cooling systems are connected respectively to the supply gallery and the exhaust gallery, formed in part by pairs of asymmetrical frame openings.

[0027] The invention also relates to a vehicle comprising at least one fuel cell as defined above.

[0028] The invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the drawings in which: - [Fig.1] [Fig.1] represents a schematic perspective view of a fuel cell according to one embodiment of the invention; - [Fig.2] [Fig.2] schematically represents the stacking of [Fig.1], shown in partially exploded perspective; - [Fig. 3] [Fig. 3] is a top view of a bipolar plate and a membrane-electrode assembly; - [Fig.4] [Fig.4] is a cross-sectional view along plane A-A' of the fuel cell stack of [Fig.2]; - [Fig. 5] [Fig. 5] is a cross-sectional view along plane B-B' of the stack of the fuel cell in [Fig. 2]; and - [Fig. 6] [Fig. 6] is a top view of a membrane assembly- electrode according to another embodiment of the invention.

[0029] Figure 1 shows a fuel cell 10 according to a first embodiment of the invention. The fuel cell 10 is, for example, intended to be used in a motor vehicle, in particular an electric vehicle, the electrical energy supplying the motor being essentially, if not entirely, supplied by the fuel cell 10.

[0030] The fuel cell 10 comprises a stack 11 comprising separator plates, here bipolar plates 12.

[0031] Each bipolar plate 12 has two opposite external faces: an anodic face and a cathodic face.

[0032] Each bipolar plate 12 is here formed by two superimposed monopolar plates 13, the two monopolar plates 13 comprising a first polar plate 13A, here a cathode plate, and a second polar plate 13B, here an anodic plate. The expression "two successive monopolar plates 13" refers to the two cathode monopolar plates 13A and anodic monopolar plates 13B combined to form a single bipolar plate 12. The monopolar plates 13 are also simply called "polar plates 13". In such a bipolar plate 12 formed by two superimposed monopolar plates 13, the anodic monopolar plate 13B forms the anodic face of the bipolar plate 12, and the cathode monopolar plate 13A forms the cathodic face of the bipolar plate 12. The anodic and cathodic faces of the bipolar plate 12 are external faces of the bipolar plate 12.

[0033] The two monopolar plates 13 are assembled together in a sealed manner. Each bipolar plate 12 has a substantially planar shape extending along a median plane P12.

[0034] In this embodiment, the two associated monopolar plates 13, which form a single bipolar plate 12, are made of metal and are welded or glued to each other, or even clamped together by a compressive force applied, according to the stacking direction Ail, on the stack 11.

[0035] The fuel cell 10 comprises a plurality of cells 14 arranged in a stack of bipolar plates 12, with each cell 14 formed between two consecutive bipolar plates 12. The stack 11, comprising several stacked bipolar plates 12, is thus made up of several individual cells 14 electrically connected in series. For each individual cell 14, the fuel cell 10 also includes a membrane-electrode assembly 50, belonging to the stack 11, which is interposed between the two bipolar plates 12 associated with that cell 14. The membrane-electrode assembly 50 is also designated as MEA 50 (abbreviation for "membrane-electrode assembly"). Thus, the stack 11 comprises several stacked bipolar plates 12 and several stacked MEA 50s, with each MEA 50 stacked between two successive bipolar plates 12.In particular, an MEA 50 is in contact on one side with the cathodic face of a first bipolar plate 12, on the other side with the anodic face of the next bipolar plate 12 in the stack 11, according to the stacking direction AIL.

[0036] Each bipolar plate 12 is thus common to two neighboring cells 14. Each membrane-electrode assembly 50 extends along a mean plane, which is parallel to the two median planes P12 associated with the bipolar plates 12 between which this membrane-electrode assembly 50 is intercalated.

[0037] The bipolar plates 12 and the MEA 50 are stacked along a stacking direction A1. The stacking direction A1 is orthogonal to the median plane P12 of the stacked bipolar plates 12 and to the mean plane of the MEA 50. In other words, the median plane P12 is a plane transverse to the stacking direction A1. A longitudinal direction L and a transverse direction T are also defined, which together with the stacking direction A1 are an orthogonal coordinate system. For each bipolar plate 12, a plate center C12 is defined for that bipolar plate 12, located in the median plane P12.

[0038] The fuel cell 10 also includes two end plates 16, which are arranged on either side of the stack 11. The stack 11 is sandwiched between the two end plates 16 and is compressed along the stacking direction. Garlic between the terminal plates 16. The terminal plates 16 are for example made of aluminum.

[0039] Supply lines 17a, 17b, 17c and discharge lines 19a, 19b and 19c shown in dashed lines in [Fig. 1] are connected to the fuel cell 10 at one of the end plates 16. In particular, the supply lines 17a, 17b, 17c and discharge lines 19a, 19b, 19c are located at the same end of the stack 11. The supply lines 17a, 17b, 17c supply the fuel cell 10 with functional fluids and the discharge lines 19a, 19b, 19c discharge the functional fluids and any reaction products that may be formed in the fuel cell 10. More specifically, there are three functional fluids: two reactive gases and a coolant. The reactant gases are hydrogen and air. The air can optionally be replaced by oxygen. The supply lines 17a, 17b and 17c supply the fuel cell 10 with hydrogen, coolant and air respectively.Supply lines 19a, 19b and 19c respectively discharge hydrogen, coolant and air possibly enriched with reaction products from fuel cell 10.

[0040] The order and relative arrangement of the pipes 17a, 17b, 17c, 19a, 19b and 19c shown in [Fig.1] is given by way of example and may be modified according to the application.

[0041] With reference to Figures 2 and 3, each bipolar plate 12 includes plate supply ports 31a, 31b and 31c and plate discharge ports 33a, 33b and 33c. In the example, a row of three plate orifices 31a, 33b and 33c is located on one side of the bipolar plate 12 along the longitudinal direction L, the three plate orifices 31a, 33b and 33c being preferentially substantially aligned in the transverse direction T. Another row, comprising three other plate orifices 31c, 31b and 33a, is located on the other side of the bipolar plate 12 along the longitudinal direction L, the three other plate orifices 31c, 31b and 33a also being preferentially substantially aligned in the transverse direction T. Thus, in the example each of the two rows is provided near a respective longitudinal end of the bipolar plate 12.However, another arrangement of the orifices is possible with, for example, a pair of orifices, or several, located on either side of the bipolar plate along the transverse direction T. The plate orifices 31a, b, c and 33a, b and c are orifices traversing the bipolar plate 12, along the stacking axis AIL. Each bipolar plate 12 comprises a peripheral zone 35, three circulation fields 36 and six homogenization fields 38. Thus, as can be seen in [Fig.3], the said row of three plate orifices 31a, 33b and 33c is located on a first longitudinal side of a circulation field. 36 while said other row, comprising three other plate orifices 31c, 31b and 33a, is located on another longitudinal side of the traffic field 36. In other words, the two rows of orifices are located longitudinally on either side of the traffic field 36.

[0042] As is well known to those skilled in the art, the circulation field 36 is the field in which the reactive gases circulate and interact with each other, notably through a membrane 58 described in more detail later. Such an interaction will not be described in further detail here, as it is well known to those skilled in the art. The circulation field 36 can also be called the "active zone." Preferably, each of the circulation fields 36 comprises a plurality of channels separated by teeth, said channels allowing the fluid flow to be properly guided. Overall, the channels extend longitudinally between, and are fluidly connected to, the homogenization fields 38.

[0043] The peripheral zone 35 extends around the entire perimeter of the bipolar plate 12, and here includes the plate orifices 31a, b, c and 33a, b, c. The plate orifices 31a, b, c, 33a, b and c, are located in the peripheral zone 35. The homogenization fields 38 and the circulation fields 36 are surrounded by the peripheral zone 35. The peripheral zone 35 extends in a plane perpendicular to the stacking direction A1l, that is to say in a plane parallel to the median plane P12.

[0044] A first circulation field 36 is formed on the anodic face of the bipolar plate 12 and extends between two first homogenization fields 38 in the longitudinal direction L. The first two homogenization fields 38 are respectively arranged between the first circulation field 36 and the plate orifices 31a, b, c, and the plate orifices 33a, b, and c, respectively, along the longitudinal direction L. In other words, the first two homogenization fields 38 are arranged on either side of the first circulation field (or active zone) 36 along the longitudinal direction L. Hydrogen flows from the plate feed orifice 31a through one of the first two homogenization fields, the first circulation field 36, and the other through one of the first two homogenization fields 38. up to the drain hole of plate 33a.Thus, the plate feed port 31a, the plate discharge port 33a, the first two homogenization fields 38, and the first circulation field 36 are fluidically connected, i.e., they are in fluidic connection with each other. The plate feed port 31a is for the injection of hydrogen, and the plate discharge port 33a, for the discharge of hydrogen, possibly enriched with reaction products.

[0045] A second circulation field 36 is formed on the cathode surface of the bipolar plate 12. It extends between two second homogenization fields 38, in the longitudinal direction L on the cathodic face of the bipolar plate 12. The two second homogenization fields 38 are arranged respectively between the second circulation field 36 and the plate orifices 31a, b, c, respectively the plate orifices 33a, b and c, along the longitudinal direction L. In other words, the two second homogenization fields 38 are arranged on either side of the second circulation field (or active zone) 36 along the longitudinal direction L. Air flows from the plate feed orifice 31c through one of the two second homogenization fields 38, the second circulation field 36, the other second homogenization field 38, to the plate discharge orifice 33c.Thus, the plate feed port 31c, the plate discharge port 33c, the two second homogenization fields 38, and the second circulation field 36 are fluidically connected, i.e., they are in fluidic connection with each other. The plate feed port 31c is for the injection of air, and the plate discharge port 33c is for the discharge of air, possibly enriched with reaction products.

[0046] A third circulation field 36 is formed inside the bipolar plate 12. It extends between the last two homogenization fields 38, in the longitudinal direction L, between the two polar plates 13 of the bipolar plate 12. The last two homogenization fields 38 are respectively arranged between the third circulation field 36 and the plate ports 31a, b, c, and the plate ports 33a, b, and c, along the longitudinal direction L. In other words, the last two homogenization fields 38 are arranged on either side of the third circulation field 36 along the longitudinal direction L. Cooling fluid flows from the plate feed port 31b through one of the last two homogenization fields 38, the third circulation field 36, the last homogenization field 38, until plate 33b drain hole.Thus, the plate inlet 31b, the plate outlet 33b, the last two homogenization fields 38, and the third circulation field 36 are fluidically connected, i.e., they are in fluidic connection with each other. The plate inlet 31b is for the injection of cooling fluid, and the plate outlet 33b, for its discharge.

[0047] Each homogenization field 38 generally comprises channels that connect one of the plate orifices 31a, b, c or 33a, b or c to the circulation field 36. In the illustrated example, the channels of the homogenization fields 38 are similar and formed in the same way as those of the circulation field 36, except for their orientation, which is fan-shaped. This geometry allows the functional fluid to be distributed throughout the circulation field 36, or the functional fluid to be recovered from the circulation field 36 and then evacuate it through the plate evacuation orifice 33a, b or c corresponding to the circulation field 36.

[0048] For each reactive gas or cooling fluid, and therefore for each fluid circulation field of the cell, the two homogenization fields 38 are preferably symmetrical with respect to a 180-degree rotation about a central plate axis A12. This rotation is parallel to the median plane P12, both in the geometry of the homogenization fields 38 and in the arrangement of the channels of the homogenization fields 38. The central axis of the plate A12 is defined, as illustrated, by an axis perpendicular to the plate plane and passing through its center. In the example in [Fig. 3], the central axis A12 is the axis projecting out of the figure, facing an observer.

[0049] The plate feed ports 31a, b, c are delimited respectively by a peripheral edge 37a, b, c, and the plate discharge ports 33a, b and c are delimited respectively by a peripheral edge 41a, b, and c, the peripheral edges 37a, b, c and 41a, b, c being closed.

[0050] The plate feed ports 31a on the one hand, and 31b and 31c on the other hand, are located symmetrically opposite each other with respect to the central axis of plate A12, and also with respect to the plate discharge ports 33a on the one hand, and 33b and 33c on the other. In other words, as can be seen in particular in [Fig. 3], the feed ports 31b and 31c are arranged on the same side, preferably in the same row, as the discharge port 33a. The discharge ports 33b and 33c are arranged on the same side, preferably in the same row, as the feed port 31a. The plate orifices 31a and 33a, 31b and 33b and 31c and 33c form respectively pairs of plate orifices 39a, 39b and 39c. Thus, the bipolar plate 12 comprises three pairs of plate orifices 39a, b and c, through which hydrogen, cooling fluid and air respectively circulate.A pair of plate orifices 39a, 39b and 39c is therefore associated with a given functional fluid. In particular, a pair of plate orifices 39a, 39b and 39c is associated with a single given functional fluid.

[0051] For each pair of plate orifices 39a, b, or c, the two plate orifices 31a, b, or c and 33a, b, or c belonging to the pair of plate orifices 39a, b, or c have symmetrical geometry, that is to say, symmetrical shape, with respect to the central axis of plate A12. For each pair of plate orifices 39a, b, or c, the two plate orifices 31a, b, or c and 33a, b, or c have, in particular, identical areas, and the peripheral edges 37a, b, or c and 41a, b, or c have a symmetrical shape with respect to the central axis of plate A12. Such symmetry simplifies the manufacturing operation of the bipolar plate 12 since each monopolar plate 13 is entirely symmetrical. In particular, the The number of punches required to create the holes is limited to three, given the symmetry of the holes in pairs. This reduces both the cost and manufacturing time. The plate holes 31a, b, c and 33a, b, c belonging to different pairs of plate holes 39a, b, c may have different areas, as shown in Figures 2 to 4.

[0052] In the illustrated example, the MEA 50 includes in particular a peripheral frame 76 also simply called a frame.

[0053] The peripheral frame 76 extends parallel to a frame plane P50. The frame plane P50 is parallel to the median plane P12 and perpendicular to the stacking direction Al1. The peripheral frame 76 preferably consists of two half-frames of substantially identical shapes intended to bear planarly against each other, and which are, for example, made of polymer film, for example polyethylene terephthalate, known by the abbreviation PET, or polyethylene naphthalate, known by the abbreviation PEN. In the latter case, the two half-frames are, for example, joined to each other by gluing.

[0054] The peripheral frame 76 comprises pairs, here three pairs of frame ports 59a, 59b and 59c and a central opening 56. The central opening 56 is intended to face the circulation field 36 (or active zone) according to the stacking direction Al 1 when the stacking 11 is realized.

[0055] Each pair of frame ports 59a, 59b, 59c consists of a single frame inlet port, respectively 51a, 51b, 51c, and a single frame outlet port, respectively 53a, 53b, 53c, for the circulation of the same given functional fluid. This given functional fluid is different from the fluid circulating in any other pair of frame ports 59a, b, c.

[0056] For example, hydrogen flows only in the pair of frame ports 59a, coolant only in the pair of frame ports 59b and air, possibly enriched with reaction products only in the pair of frame ports 59c.

[0057] The frame feed ports 51a, b, c are each respectively delimited by a peripheral edge 57a, 57b, and 57c, and the frame discharge ports 53a, b, and c are each respectively delimited by a peripheral edge 61a, 61b, and 61c, the peripheral edges 57a, b, c and 61a, b, c being closed. Here, the peripheral edges 57a, b, c and 61a, b, c are closed curves, forming polygons with rounded corners. Alternatively, the peripheral edges 57a, b, c and 61a, b, c are broken lines forming polygons with sharp corners, for example, four corners.

[0058] The frame supply and discharge ports 51a, b, c and 53a, b, c surround the central opening 56. More specifically, as illustrated, the supply and The frame discharge ports 51a, b, c and 53a, b, c are located along the longitudinal direction L on either side of the central opening 56. The frame supply and discharge ports 51a, b, c and 53a, b, c are provided in the frame 76 to allow the circulation of functional fluids through the MEA 50 along the stacking direction Ail. Each frame supply port 51a, b, c is designed to extend one of the plate supply ports 31a, b, or c of the bipolar plate 12 along the stacking direction Ail. Similarly, each frame discharge port 53a, b, c is designed to extend one of the plate discharge ports 33a, b, or c, respectively, along the stacking direction Ail. In other words, the plate feed holes 31a, b, c are respectively intended to be opposite the frame feed holes 51a, b and c in the stacking direction Ail.Similarly, the plate discharge ports 33a, b, c are respectively intended to be opposite the frame discharge ports 53a, b and c in the stacking direction Ail. Each frame supply and discharge port 51a, b, c and 53a, b and c delimits a section, parallel to the frame plane P50.

[0059] For each pair of frame holes 59a, b, c, the frame holes 51a, b, c and 53a, b, c are located symmetrically opposite each other with respect to a central frame axis A50 parallel to the stacking direction Al 1 and passing through a frame center C50. The central frame axis A50 is defined, as illustrated, by an axis perpendicular to the plane of the frame 76 and passing through its center. In the example in [Fig. 3], the central axis A50 is the axis projecting out of the figure, facing an observer.

[0060] One of the frame hole pairs, here frame hole pair 59a, is a symmetrical frame hole pair, meaning that the two frame holes 51a and 53a of frame hole pair 59a are symmetrical with respect to the frame's central axis A50. In other words, the two frame holes 51a and 53a are symmetrical with respect to a 180-degree rotation about the frame's central axis A50, the rotation occurring in the frame plane P50, and have the same area. The symmetrical frame hole pair 59a is also called a symmetrical hole pair. This simplifies the shape of frame 76 and therefore its manufacture, notably by allowing the use of a single punch for making both holes 51a and 53a of the symmetrical pair 59a. The manufacturing time and cost of frame 76 are thus reduced.

[0061] The peripheral edges 37a, 41a, b, c of the plate feed holes 31a and plate discharge holes 33a, b, c and the peripheral edges 57a, 61a, b, c of the frame feed holes 51a and frame discharge holes 53a, b, c which are intended to be stacked in the stack 11 may not coincide exactly, so that the cross-sectional area of ​​the holes 51a, 53a, b or c is, for example, respectively less than an area of ​​the section of the orifice 31a, 33a, b or c. However, the peripheral edges 41a, b, c and 61a, b, c of the superimposed plate and frame evacuation orifices 33a, b, c and 53a, b, c may have the same shape.

[0062] For example, a shape of the peripheral edge 61a of the frame discharge port 53a may be a homothety with a factor of less than 1 of a shape of the peripheral edge 41a of the plate discharge port 33a. This arrangement limits the risk of two bipolar plates 12 being in direct contact, without there being a separation ensured by the frame 76 at the plate ports 31a, b, c and 33a, b, c. Indeed, in this case, the frame 53a discharge orifice is smaller than the plate 33a discharge orifice, so there is locally more insulating material of the peripheral frame 76 than conductive material of the bipolar plates 12, which limits any risk of contact between two bipolar plates 12. This limits the risk of short circuits between two bipolar plates 12 at the plate orifices 31a, b, c and 33a, b, c.

[0063] Another of the given pairs of frame holes, here pairs 59b and 59c, are pairs of asymmetrical frame holes, that is to say that the frame holes 51b or c and 53b or c belonging to this pair of frame holes 59a, b, c are asymmetrical with respect to the central frame axis A50. In other words, the frame holes 51b or c and 53b or c belonging to this pair of frame holes 59b, c are asymmetrical with respect to a rotation of 180 degrees of angle with respect to the central frame axis A50. Thus, for the pairs of asymmetric frame openings 59b and 59c, openings 51b and 53b on the one hand, and 53b and 53c on the other, have different geometries, that is, different shapes and / or different areas. The pairs of asymmetric frame openings 59b and 59c are also called pairs of asymmetric openings.In other words, the inlet port 51b or 51c of the frame of the asymmetric pair 59b or 59c does not have the same shape and / or area as the outlet port 53b or 53c of said pair. Such asymmetry makes it possible to manage and generate a different fluid flow at the inlet and outlet. This is particularly advantageous and desirable when, for example, one wants to compensate for certain pressure losses or limit them, or more generally, ensure a homogeneous flow of reactive fluid in the cells 14 constituting the stack 11.

[0064] For each pair of asymmetrical orifices 59b, c, an area of ​​the cross-section of the frame feed orifice 51b or c is advantageously smaller than an area of ​​the cross-section of the frame discharge orifice 53b or c. Thanks to this feature, the cross-section of the frame discharge orifice 53b or c can be intentionally increased, so as to facilitate and encourage fluid flow towards the frame discharge orifice 53b or c. This prevents possible overpressure or "blockage" phenomena. » downstream of the frame drain port 53b or c and ensures good fluid circulation, especially in the active zone 36.

[0065] For example, for pairs of asymmetrical ports 59b, 59c, the cross-sectional area of ​​the frame feed port 51b or c is advantageously smaller than the cross-sectional area of ​​the frame discharge port 53b or c by a factor of between 5% and 50%, and preferably between 8% and 33%. The reduction factor between the cross-sectional areas of the frame feed and discharge ports 51b, c and 53b, c may differ from one pair of asymmetrical frame ports 59b, c to another. For example, the area reduction factor for the pair of asymmetrical frame ports 59b may be between 15% and 35%, and the area reduction factor for the pair of asymmetrical frame ports 59c may be between 10% and 30%.This allows, in particular, for the adjustment of flow conditions for each functional fluid and ensures, on the one hand, optimal reaction conditions for the two reactive gases, and on the other hand, optimal cooling by the cooling fluid.

[0066] For each pair of asymmetrical orifices 59b, c, the peripheral edge 57b, c of each frame feed orifice 51b, c comprises an overlapped portion and an overhanging portion, i.e., each comprises respectively an overlapped portion 64b, 64c and an overhanging portion 65b and 65c. The peripheral edge 61b, c of each frame discharge orifice 53b, c comprises an overlapped portion and a recessed portion, i.e., each comprises respectively an overlapped portion 68b, 68c and a recessed portion 69b, 69c.

[0067] By "portion" is meant a portion of the peripheral edge, that is to say in the case where the peripheral edge has the shape of a polygon or a closed curve forming rounded angles, a single segment or a plurality of successive segments forming a part of the peripheral edge, as can be seen in [Fig.3].

[0068] Regarding the expressions "overlapping portion", "overhanging portion" and "recessed portion", the following explanation is given for pair 59b, but is also valid for pair 59c.

[0069] The overlapping portion 64b of the frame feed port 51b is identical in shape to the overlapping portion 68b of the frame discharge port 53b after a 180-degree rotation about the frame central axis A50. In other words, the overlapping portions 64b and 68b are symmetrical with respect to the frame central axis A50. In other words, if the frame feed and discharge ports 51b and 53b were superimposed following a 180-degree rotation of one of the frame feed and discharge ports 51b and 53b about the frame central axis A50, then the overlapping portions 64b and 68b would coincide (i.e., "overlap"). In this case, the portions superimposed 64b and 68b (or 68c and 64c) comprise several successive segments of the peripheral edge 57b and 61b, as can be seen in [Fig.3].

[0070] Conversely, the overhanging portion 65b is more overhanging towards the inside of the frame feed orifice 51b than is the recessed portion 69b towards the inside of the frame discharge orifice 53b. In other words, if the frame supply and discharge ports 51b and 53b were superimposed such that the superimposed edges 64b and 68b coincide, the overhanging portion 65b would be offset inwards from the port (i.e., "overhang" inwards) relative to the recessed portion 69b (i.e., "recessed from the port"), as can be seen by comparing Figures 4 and 5. The overhanging portion 65b is therefore more offset inwards from the frame supply port 51b than the recessed portion 69b is offset inwards from the frame discharge port 53b.In this case, the projecting portion 65b comprises a single segment of the peripheral edge 57b, the segment having curved ends, and the recessed portion 69b comprises two segments of the peripheral edge 61b, joined by a rounded angle 61b. In other words, the projecting portion 65b allows for the formation of a frame inlet 51b with a smaller area than the frame outlet 53b, and it is the projecting portion 65b and the recessed portion 68b that are asymmetrical with respect to each other. Thus, the two frame outlets 51b, or c and 53b, or c of a pair of asymmetrical outlets 59b, c are therefore of different shape, in the sense of different geometry, in addition to being of different area, as mentioned previously.

[0071] The superimposed portion 64b is ideally located between the overhanging portion 65b and the central opening 56. Thus, the overhanging portion 65b is the portion of the peripheral edge 57b that is furthest from the central part 56. This makes it possible to move potential turbulence away from the central opening 56 and to limit any resulting feed disparities.

[0072] The central opening 56 is intended to be opposite the circulation field 36 in the stacking direction AIL

[0073] With reference to Figures 2 to 4, the MEA 50 comprises the membrane 58, which is a proton exchange polymer membrane. The membrane 58 extends parallel to the frame plane P50, opposite the circulation field 36 along the stacking direction Al 1, and is substantially planar. The membrane 58 can be coated with a catalyst layer on its two faces parallel to the frame plane P50.

[0074] The frame 76 is designed to support the membrane 58. In the example of [Fig. 3], the membrane 58 is inserted into the central opening 56. The frame 76 clamps an outer peripheral edge of the membrane 58, in the stacking direction A1, in order to hold the membrane 58. The frame 76 then clamps a portion of the membrane 58 along the stacking direction AIL

[0075] The membrane 58 of each MEA 50 is taken between two gas diffusion layers 77, also called GDL, an acronym for the English "Gas Diffusion Layer", visible in figures 4 and 5. Each gas diffusion layer 77 extends parallel to the frame plane P50 and is interposed between the membrane 58 and the bipolar plate 12 opposite, following the stacking direction Ail.

[0076] In the illustrated example, each gas diffusion layer 77 completely covers the membrane 58 and advantageously extends over the inner periphery of the frame 76 that clamps the membrane 58. The gas diffusion layer 77 is advantageously made of a porous material and allows the reactive gas to diffuse from the circulation fields 36 to the membrane 58 when the cell 14 is operating. In particular, one of the two gas diffusion layers 77 is in contact with the cathodic face of one of the bipolar plates 12 of the stack 11, so air can diffuse through the gas diffusion layer 77 until it reaches the membrane 58, and the other gas diffusion layer 77 is in contact with the anodic face of the next bipolar plate 12 in the stack, allowing hydrogen to diffuse through the gas diffusion layer 77 to the membrane 58.

[0077] Seals 79, visible in figures 4 and 5, interposed between the bipolar plates 12 and the MEA 50 in the direction of the stacking Ail, allow the functional fluids to circulate only in the circulation fields 36 dedicated to them, for example the reactive field 36 of the cathodic face of the bipolar plate 12 for air or oxygen, and the reactive field 36 of the anodic face of the bipolar plate 12 for hydrogen, and prevent the functional fluids from mixing.

[0078] In the stack 11, the plate and frame feed ports 31a, b, c and 51a, b, c and the plate and frame discharge ports 33a, b, c and 53a, b, c together form feed galleries 81a, 81b, 81c and discharge galleries 83a, 83b and 83c, respectively, internal to the stack 11, also called "internal manifold" in English. In particular, three feed galleries 81a, b, c and three discharge galleries 83a, b, c are formed respectively by the plate and frame feed ports 31a, b, c and 51a, b, c and by the plate and frame feed ports 33a, b, c and 53a, b and c. In the same way as for the orifices, pairs of galleries 89a, 89b and 89c are defined, corresponding to the pairs 39a, b, c and 59a, b, c of plate and frame orifices.

[0079] A given functional fluid flows through a single pair of galleries 89a, b or c. In particular, a given functional fluid flows through a single supply gallery 81a, b or c, supplies one of the circulation fields 36 and is discharged through a single discharge gallery 83a, b or c, this discharge gallery 83a, b, c belonging to the same pair as the supply gallery 81a, b, c.

[0080] Useful sections of the feed galleries 81a, b, c are defined by the smallest section of the orifices forming the feed gallery 81a, b, c, i.e.- The cross-sectional areas of the frame supply ports 51a, b, and c are defined respectively. The effective cross-sectional areas of the discharge gallery 83a, b, and c are defined by the cross-sectional areas of the frame discharge ports 53a, b, and c, according to the frame plans P50. Thus, thanks to the invention, it is possible to manage the effective cross-sectional area of ​​the supply galleries solely by the cross-sectional areas of the frame ports 59a, 59b, and 59c, thereby compensating for pressure variations between the supply and discharge galleries due to the circulation of functional fluids and pressure losses from friction. In particular, this allows for maintaining a substantially constant pressure difference between two galleries 81a, b, or c and 83a, b, or c belonging to the same pair of galleries 89a, b, and c, regardless of their position along the galleries.The advantage of combining pairs of symmetrical orifices 59a and asymmetrical orifices 59b, 59c, applied solely to the frame 76, then becomes clear: by modifying the orifices on this single component, it is possible to influence and control the fluid flow in the supply gallery 81a, b, c and / or the discharge gallery 83a, b, c. The invention becomes particularly interesting when one considers that the frame 76 is one of the least expensive components of the stack 11, since, as mentioned previously, it is a polymer sheet. In particular, the frame 76 is much less expensive than a bipolar plate 12, so it is quite practical to retain a symmetrical bipolar plate 12 (simpler and therefore less expensive) and concentrate the asymmetry on the least expensive component, in this case, the frame 76.

[0081] For the pair of galleries 89a, the areas of the useful sections of the supply gallery 81a are equal to the areas of the useful sections of the evacuation gallery 83a.

[0082] For the pair of galleries 89b, the areas of the effective cross-sections of the supply gallery 81b are less than the areas of the effective cross-sections of the discharge gallery 83b, as a consequence of the fact that the cross-sectional area of ​​each frame supply orifice 51b is less than the cross-sectional area of ​​the frame discharge orifice 53b. The same is true for the pair of galleries 89c.

[0083] According to an unshown variant, within the same stack 11, the frame feed ports 51a, b, c, which together define the same feed gallery 81a, b, c, do not all have the same cross-section. For example, two different frame feed ports 51a have different cross-sectional areas. Thus, the feed gallery 81a has variable effective cross-sectional areas along its length depending on the stacking direction A1. The MEA 50 are, for example, arranged such that the cross-sectional areas of the frame feed ports increase in the direction of flow of one of the functional fluids. This allows for better optimization of the functional fluid flow, since in addition to adapting the effective cross-sectional area of ​​the feed galleries, the effective cross-sectional area is also adapted along the same gallery.

[0084] The supply galleries 81a, b, c are respectively connected to the supply lines 17a, b, c, which supply the supply galleries 81a, b and c respectively with hydrogen, coolant and air, and the exhaust galleries 83a, b, c are respectively connected to the exhaust lines 19a, b, c which exhaust the hydrogen, the coolant and the air and possibly the reaction products, which allows the fuel cell 10 to operate and in particular to generate electricity.

[0085] Figure 6 shows an alternative embodiment of an MEA 150. Aspects of the MEA 150 that are identical to those of the MEA 50 described in Figures 1 to 5 are referenced with the same reference numerals and are not described again in detail. The MEA 150 can be used in the same way as the MEA 50, in particular as a replacement for the MEA 50 in stacking 11.

[0086] The MEA 150 differs from the MEA 50 in that it includes frame feed ports 151a, b, c, which replace the frame feed ports 51a, b, c and frame discharge ports 153a, b, c which replace the discharge ports 53a, b and c. The feed ports 151a, b, c are respectively delimited by a peripheral edge 157a, b, c, which replaces the peripheral edges 57a, b, c. The peripheral edges 157a, b, c are closed broken lines, each peripheral edge 157a, b, c forming a polygon with corners, in other words with sharp angles.

[0087] The feed ports 151a, b, c are made in the peripheral frame 76. Each frame feed port 151a, b and c delimits a section, parallel to a frame plane P150.

[0088] Similarly, the drainage orifices 153a, b, c are respectively delimited by a peripheral edge 161a, b, c, which are closed broken lines forming a polygon with corners.

[0089] As with the MEA 50, in the MEA 150, the frame holes 151a, b, c and 153a, b and c, which are located symmetrically opposite each other with respect to a central frame axis A150 parallel to the stacking direction Al 1 and passing through a frame center C150, form pairs of frame holes 159a, 159b and 159c, which respectively replace the pairs of frame holes 59a, b and c. The pairs of frame holes 159a, 159b and 159c are respectively similar to the pairs of frame holes 59a, b and c. Thus, the MEA 150 comprises three pairs of frame holes 159a, 159b and 159c.

[0090] The frame holes 151a and 153a belonging to the pair of frame holes 159a are symmetrical with respect to the central axis A150. In other words, the two frame holes 151a and 153a are symmetrical in shape with respect to the central frame axis A150 and have the same area. The pair of frame holes 159a is therefore a pair of symmetrical frame holes, also called a pair of symmetrical holes.

[0091] An area of ​​the cross-section of the frame feed orifice 151a is equal to an area of ​​the cross-section of the frame discharge orifice 153a.

[0092] The following description describes only the asymmetric orifice pair 159b, but this description is valid for the asymmetric orifice pairs 159b and 159c. For the frame orifice pair 159b, the two frame orifices 151b and 53b belonging to this frame orifice pair 159b are asymmetric with respect to the central axis A150 and are said to be asymmetric frame orifice pairs 159b, or simply asymmetric orifice pairs.

[0093] In particular, the two frame ports 151b and 153b have different geometries, i.e., different shapes and / or different areas. Advantageously, the cross-sectional area of ​​the frame feed port 151b is less than the cross-sectional area of ​​the frame discharge port 153b.

[0094] For the asymmetrical orifice pair 159b, the cross-section of the frame feed orifice 151b is advantageously less than the cross-section of the frame discharge orifice 153b by the same factor as has been described for the MEA 50.

[0095] The reduction factor between the cross-sectional areas of the frame supply and discharge ports 151b, c and 153b and c may be different for the frame port pairs 159b and 159c, as described for the MEA 50.

[0096] The peripheral edge 157b, c of each frame feed orifice 151b, c comprises respectively an overlapped portion 164b, 164c and an overhanging portion 165b, 165c. The peripheral edge 161b, c of each frame discharge orifice 153b, c comprises respectively an overlapped portion 168b, 168c and a recessed portion 169b, 169c.

[0097] The overlapping portion 164b of the frame feed port 151b is identical in shape to the overlapping portion 168b of the frame discharge port 153b after a 180-degree rotation around the central axis A150, in the plane of the plate P150. The projecting portion 165b is offset further inward from the frame feed port 151b than the recessed portion 169b is inward from the frame discharge port 153b. The same is true for the overlapping portions 164c and 168c, and the projecting portion 165c and the recessed portion 153c.

[0098] The overhanging portion 165b of the MEA 150 is a broken line forming several corners.

[0099] The overhanging portion 165c is, in the example of [Fig. 6], a straight line connecting two ends of the superimposed portion 164c. In particular, the overhanging portion 165c does not form corners, unlike the recessed portion 168c, which is a line broken, with one or more breaks forming one or more corners. Thus, the overhanging portion 165c does not form any of the corners of the peripheral edge 157c. More precisely, the overhanging portion 165c forms corners of the peripheral edge 157c only through its intersection with the overlapping portion 164c, but does not by itself form one or more corners of the peripheral edge 157c.

[0100] The straight line shape allows us to maintain a peripheral edge geometry 157c that is as simple as possible, in order to limit pressure losses and optimize the circulation of functional fluids, here air, through the frame supply ports 151c and 153c.

[0101] According to an unrepresented variant, the overhanging portion may still be a curved line, in particular to facilitate the manufacture of the orifices 151b, c and 153b, c.

[0102] Thus, the supply galleries 81a, b, c and the evacuation galleries 83a, b and c have their useful cross-sections optimized. This is achieved by means of the MEA 50 or 150, and does not depend on the orientation of the bipolar plates 12, which are arranged in the stack 11 symmetrically with respect to the central axis A12

[0103] The embodiments and variants mentioned above can be combined with each other to generate new embodiments of the invention.

Claims

Demands

1. A peripheral frame (76) for a membrane-electrode assembly (50; 150) of a fuel cell (10), the frame (76) extending parallel to a frame plane (P50), characterized in that the frame (76) comprises pairs of frame ports (59a, 59b, 59c; 159a, 159b, 159c), each pair of frame ports (59a, 59b, 59c; 159a, 159b, 159c) consisting of a single frame inlet port (51a, 51b, 51c; 151a, 151b, 151c) and a single frame outlet port (53a, 53b, 53c; 153a, 153b, 153c) for circulation of the same given functional fluid, which is different from the fluid circulating in any other pair of frame ports (59a, 59b, 59c; 159a, 159b, 159c) of the peripheral frame (76), the frame supply port (51a, 51b, 51c; 151a, 151b, 151c) and the frame discharge port (53a, 53b, 53c; 153a, 153b, 153c) being arranged symmetrically opposite each other with respect to a central frame axis (A50;A150) perpendicular to the frame plane (P50) and passing through a frame center (C50), one of the pairs of frame holes (59a; 159a) is a symmetric pair of frame holes in that the two frame holes (51a; 151a, 53a; 153a) of the pair of frame holes (59a; 159a) are symmetric with respect to the central frame axis (A50; A150), another of the pairs of frame holes (59b, 59c; 159b, 159c) is an asymmetric pair of frame holes in that the two frame holes (51b, 51c; 151b, 151c, 53b, 53c; 153b, 153c) of the asymmetric pair of frame holes (59b, 59c; 159b, 159c) are asymmetrical with respect to the central axis of the frame (A50; A150).

2. Frame according to claim 1, wherein each frame orifice (51a, 51b, 51c, 53a, 53b, 53c; 151a, 151b, 151c) delimits a section, parallel to the frame plane (P50), and for the pair of asymmetrical frame orifices (59b, 59c; 159b, 159c), an area of ​​the frame feed orifice section (51b, 51c; 151b, 151c) is less than an area of ​​the frame discharge orifice section (53b, 53c), advantageously by a factor of between 5% and 50%, preferably between 8% and 33%.

3. Frame according to any one of the preceding claims, wherein each frame opening (51a, 51b, 51c, 53a, 53b, 53c; 151a, 151b, 151c) is delimited by a respective peripheral edge (57a, 57b, 57c, 61a, 61b, 61c ; 157a, 157b, 157c), and for the pair of asymmetric frame ports (59b, 59c ; 159b, 159c): - the peripheral edge (57b and 57c ; 157b, 157c) of the frame feed port (51b, 51c ; 151b, 151c) comprises an overlapping portion (64b, 64c ; 164b, 164c) and an overhanging portion (65b, 65c ; 165b, 165c); - the peripheral edge (61b, 61c) of the frame discharge port (53b, 53c) comprises an overlapped portion (68b, 68c) and a recessed portion (69b, 69c); - the overlapped portion (64b, 64c; 164b, 164c) of the frame feed port (51b, 51c; 151b, 151c) is identical in shape to that of the overlapped portion (68b, 68c) of the frame discharge port (53b, 53c); and - the overhanging portion (65b, 65c; 165b, 165c) is further offset towards the interior of the frame feed port (51b, 51c;151b, 151c) than the recessed portion (69b, 69c) towards the inside of the frame drain hole (53b, 53c).;

4. Frame (76) according to claim 3, wherein the overlapping portion (64b, 64c; 164b, 164c) of the frame feed orifice (51b, 51c; 151a, 151b, 151c) is disposed between the overhanging portion (65b and 65c; 165b, 165c) and a central opening (56) of the frame (76).

5. Frame according to claim 3 or 4, wherein for the pair of asymmetric frame ports (159c): - the peripheral edge (161c) of the frame discharge port (153c) forms corners; - the peripheral edge (157c) of the frame feed port (151c) forms corners; - the recessed portion (169c) forms at least one of the corners of the peripheral edge (161c) of the frame discharge port (153c); and - none of the corners of the peripheral edge (157c) of the frame feed port (151c) are formed by the overhanging portion (165c).

6. Electrode membrane assembly (50) comprising:

7. - a membrane (58); and - a frame (76) according to any one of the preceding claims, the membrane (58) extending parallel to the frame plane (P50) and the frame (76) surrounding the membrane (58). Stack (11), for a fuel cell (10), the stack (11) comprising: - a separator plate (12), extending perpendicularly to a stacking direction (Al 1), the separator plate (12) comprising: • a circulation field (36), and • a peripheral zone (35) surrounding the circulation field (36) and comprising two pairs of plate orifices (39a, 39b, 39c), each pair of plate orifices (39a, 39b, 39c) comprising a plate feed orifice (31a, 31b, 31c) and a plate discharge orifice (33a, 33b, 33c), fluidically connected by the circulation field (36), such that for each pair of plate orifices (39a, 39b, 39c), a functional fluid flowing through the plate feed orifice (31a, 31b, 31c) also flows through the plate discharge orifice (33a, 33b, 33c); and - a membrane-electrode assembly (50; 150) according to claim 6, superimposed on the separating plate (12), the frame supply ports (51a, 51b, 51c; 151a, 151b, 151c) and frame discharge ports (53a, 53b, 53c) of the same pair of frame ports (59a, 59b, 59c; 159a, 159b, 159c) being respectively superimposed on the plate supply and discharge ports (31a, 31b, 31c, 33a, 33b, 33c) of the same pair of plate ports (39a, 39b, 39c), such that the given functional fluid flows through the frame supply port (51a, 51b, 51c; 151a, 151b, 151c) and the frame discharge port (53a, 53b, 53c) belonging to the same pair of frame ports (59a, 59b, 59c) also flows through the plate feed port (31a, 31b, 31c) and plate discharge port (33a, 33b, 33c) superimposed, belonging to the same pair of plate ports (39a, 39b, 39c), the plate and frame feed ports (31a, 31b, 31c, 51a, 51b, 51c; 151a, 151b, 151c) superimposed, forming respectively part of two feed galleries (81a, 81b, 81c) parallel to the stacking direction (A1), and the plate and frame discharge ports (33a, 33b, 33c, 53a, 53b, 53c) superimposed, forming part of two discharge galleries (83a, 83b, 83c), parallel to the stacking direction (A1), so that one of the given functional fluids flows in a single feed gallery (81a, 81b, 81c), feeds the circulation field (36), and is evacuated through a single evacuation gallery (83a, 83b, 83c).

8. Stack (11) according to claim 7, comprising several membrane-electrode assemblies (50), and several separator plates (12), alternately superimposed in the stacking direction (Ail).

9. Fuel cell (10) comprising: - a stack (11) according to any one of claims 7 to 8; and - two supply lines (17a, 17b, 17c) in a given respective functional fluid, each line being connected to a single supply gallery (81a, 81b, 81c) to supply this supply gallery (81a, 81b, 81c) with respective functional fluid, and two discharge lines (19a, 19b, 19c), each connected to a single discharge gallery (83a, 83b, 83c) to discharge the respective functional fluid from the discharge gallery (83a, 83b, 83c).

10. Fuel cell (10) according to claim 9, wherein one of the functional fluids is hydrogen, and the hydrogen supply line (17a) and the hydrogen discharge line (19a) are connected respectively to the supply gallery (81a) and the discharge gallery (83a) formed in part from the symmetrical pairs of frame ports (59a; 159a).

11. Fuel cell (10) according to claim 9 or 10, wherein one of the functional fluids is oxygen, and the oxygen supply line (17c) and the exhaust line (19c) is oxygen. oxygen are connected respectively to the supply gallery (81a) and the exhaust gallery (83c) formed in part from pairs of asymmetrical frame orifices (59c; 159c).

12. Fuel cell (10) according to any one of claims 9 to 11, wherein one of the functional fluids is a coolant fluid, and the coolant supply line (17b) and the coolant discharge line (19b) are connected respectively to the supply gallery (81b) and the discharge gallery (83b) formed in part from the pairs of asymmetric frame ports (59b; 159b).

13. Vehicle comprising at least one fuel cell (10) according to any one of claims 9 to 12.

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