Associated polar plate, polar separator, bipolar separator, stack and fuel cell

Abstract

The present invention relates to a polar plate (10) for a fuel cell, the polar plate (10) comprising a flow field comprising walls (40) and channels for guiding a flow of reactive fluid; a rim (50), which is bordered by a final wall (41) and extends the primary plate beyond the flow field; a lateral sealing location (54) provided to receive a peripheral seal; and a bypass zone (56), which is formed on the rim and delimited by the lateral sealing location and the final wall and allows a flow of reactive fluid to bypass the flow field. In order to stiffen the bypass zone, the polar plate comprises a stiffening relief (60), which is formed by the primary face on the rim, is disposed in the bypass zone between the final wall and the lateral sealing location and extends continuously over at least 75% of the length of the flow field.

Description

[0001] TITLE: POLAR PLATE, POLAR SEPARATOR, BIPOLAR SEPARATOR, ASSOCIATED FUEL STACK AND BATTERY

[0002] The present invention relates to a polar plate for a fuel cell stack, a polar separator comprising such a polar plate, a stack comprising such a polar separator and a fuel cell comprising such a stack.

[0003] A fuel cell stack comprises several electrochemical cells, each cell including a membrane-electrode assembly with a proton exchange membrane surrounded by two gas diffusion layers. Each cell also includes two pole plates surrounding the membrane-electrode assembly. Each pole plate separates the electrochemical cell from one of two adjacent electrochemical cells and allows the supply of a reactive gas, such as oxygen or hydrogen, to one of the two faces of the membrane-electrode assembly. Thus, each pole plate has a reactive gas inlet and outlet, and a flow field with walls delimiting channels guides the flow of primary reactive fluid from the inlet to the outlet. This flow passes through a gas diffusion layer of the membrane-electrode assembly.

[0004] It is common practice to include a bypass zone on each pole plate, positioned on either side of the flow field, to allow the primary reactive fluid to flow from the inlet port to the outlet port, bypassing the flow field. This bypass zone is generally referred to as a "bypass zone." The bypass zone is delimited on one side by the flow field and on the other by a peripheral sealing element of the stack, such as a perimeter seal, which contains the reactive fluid on the surface of the pole plate.

[0005] A common problem with fuel cell stacks concerns the stiffness of the pole plate, which is often low due to its thinness. Generally, the pole plate stiffness is adequate in the circulation field, as the channel walls stiffen the circulation field, but it is insufficient in the bypass zone.

[0006] To resolve this issue, WO-2016 / 142619-A1 proposes adding reinforcing ducts on either side of the traffic area. These ducts are closed and each receives mechanical reinforcement, such as a rectangular beam. While this solution is effective in stiffening the polar plate, it has the disadvantage of being complex to implement, expensive, and bulky, notably by increasing the thickness of the polar plate, and therefore that of the cell and the stack.

[0007] One aim of the invention is therefore to propose a new polar plate which, while being rigid at the bypass zone, is simple to manufacture, inexpensive and compact.

[0008] To this end, the invention relates to a pole plate for a fuel cell stack, the pole plate extending perpendicularly to a stacking direction, the pole plate defining a distinct longitudinal and transverse direction perpendicular to the stacking direction, the pole plate comprising a primary face oriented in the stacking direction, the pole plate comprising:

[0009] a feed port, passing completely through the polar plate from the primary face,

[0010] an evacuation orifice, passing completely through the polar plate from the primary face,

[0011] a circulation field, formed by the primary face and comprising walls, projecting along the stacking direction, extending in the longitudinal direction and delimiting channels to guide a flow of primary reactive fluid from the supply port to the discharge port, the walls comprising a final wall delimiting the circulation field,

[0012] an edge, formed by the primary face and extending the primary plate beyond the circulation field in the transverse direction, the last wall bordering the edge to prevent flow of the primary reactive fluid from the circulation field to the edge,

[0013] a lateral sealing location, formed by the rim, the lateral sealing location being configured to receive a longitudinal portion of a peripheral sealing element, the longitudinal portion extending over the entire length of the circulation field, measured along the longitudinal direction, the peripheral sealing element being configured to contain the primary reactive fluid on the surface of the primary face,

[0014] a bypass zone, formed by the primary face on the rim and delimited in the transverse direction by the last wall and by the lateral sealing location, the bypass zone being configured to allow a flow of primary reactive fluid from the supply port to the discharge port bypassing the circulation field, and a stiffening relief,

[0015] formed by the primary face on the edge, between the last wall and the lateral sealing location, in the transverse direction, the stiffening relief being arranged in the bypass area, and extending continuously over at least 75% of the length of the traffic area, in the longitudinal direction.

[0016] One idea underlying the invention is to form a longitudinal relief directly in the bypass zone of the polar plate, for example, by stamping. Such a stiffening relief is sufficient to stiffen the polar plate when it extends continuously over a sufficient length of the flow field, does not affect the proper functioning of the stack, and / or does not increase the thickness of the polar plate. In particular, since the stiffening relief is formed directly in the bypass zone, it is especially effective at stiffening the bypass zone without impeding the flow of the primary reactive fluid in the bypass zone.Furthermore, the stiffening relief can advantageously accommodate a filler seal, formed simultaneously with the peripheral sealing gasket. The filler seal allows the stiffening relief to be sealed, thus preventing the flow of primary reactive fluid into the bypass zone. In addition, the filler seal can contribute to improving the rigidity of the pole plate and anchoring the peripheral sealing gasket to the pole plate.

[0017] According to other advantageous aspects of the invention, the invention comprises one or more of the following features, taken individually or in all technically possible combinations:

[0018] - A ratio of a smaller width of the bypass area, measured along the transverse direction, to a larger width of the traffic field channels, measured along the transverse direction, is greater than 2.5, preferably greater than 4, preferably even greater than 7.

[0019] - A smaller distance between the stiffening relief and the last wall, measured along the transverse direction, is greater than 2 mm, preferably greater than 5 mm.

[0020] - The width of the stiffening relief, measured along the transverse direction, is constant and is preferably between 0.30 mm and 2 mm.

[0021] - The stiffening relief extends over at least 90% of the length of the traffic field.

[0022] - The stiffening relief is rectilinear and extends parallel to the longitudinal direction.

[0023] - The stiffening relief forms a hollow relative to the primary face. - A height of the stiffening relief, measured from the primary face parallel to the stacking direction, is less than a height of the walls and a height of the channels, measured from the primary face parallel to the stacking direction.

[0024] - The polar plate further comprises groups of auxiliary stiffening reliefs, the groups being aligned with each other and spaced, along the longitudinal direction, each group comprising at least two auxiliary stiffening reliefs, formed by the primary face on the rim, between the last wall and the lateral sealing location, along the transverse direction, the auxiliary stiffening reliefs being arranged in the bypass zone, and in each group, the auxiliary stiffening reliefs are nested along the longitudinal direction and along the transverse direction.

[0025] - The groups of auxiliary stiffening reliefs are located between the stiffening relief and the last wall, according to the transverse direction.

[0026] According to another aspect, the invention also relates to a polar separator comprising the polar plate as described above and a peripheral seal received on the primary face of the polar plate, the peripheral seal forming the peripheral sealing member, a longitudinal portion of the peripheral seal being received in the lateral sealing location.

[0027] Advantageously, the polar separator further comprises at least one slowing fin, made of material with the peripheral joint, said at least one slowing fin extending from the peripheral joint towards the circulation field by crossing the stiffening relief.

[0028] Advantageously, the polar separator also includes a filler joint that fills the stiffening relief, which is formed by the material along with the peripheral joint. Preferably, the filler joint is flush with the primary face, parallel to the stacking direction.

[0029] According to another aspect, the invention also relates to a bipolar separator comprising a first polar plate as described above; a first peripheral seal received on the primary face of the first polar plate, a longitudinal portion of the first peripheral seal being received in the lateral sealing location of the first polar plate, the first peripheral seal forming the peripheral sealing element associated with the first polar plate; a second polar plate as described above; and a second peripheral seal received on the primary face of the second polar plate, a longitudinal portion of the second peripheral seal being received in the lateral sealing location of the second polar plate, the second peripheral seal forming the peripheral sealing element associated with the second polar plate. The first polar plate and the second polar plate are stacked in the direction of stacking.The stiffening relief of the first polar plate is opposite the stiffening relief of the second polar plate, according to the stacking direction.

[0030] According to another aspect, the invention also relates to a stack comprising the polar separator as described above, and a membrane-electrode assembly, extending perpendicularly to the stacking direction, which is superimposed on the polar separator, such that the membrane-electrode assembly is arranged in the stacking direction relative to the polar separator. The membrane-electrode assembly comprises an exchange zone, including a proton exchange polymer membrane, a peripheral zone surrounding the exchange zone and extending the exchange zone in the transverse direction, and a primary gas diffusion layer.The circulation field is aligned, along the stacking direction, with the exchange zone and with the primary gas diffusion layer, the gas diffusion layer being interposed between the circulation field and the exchange zone along the stacking direction, and the rim is aligned with the peripheral zone, along the stacking direction.

[0031] According to another aspect, the invention also relates to a fuel cell comprising the stack or bipolar separator as described above.

[0032] 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:

[0033] [Fig. 1] Figure 1 is a perspective view of a fuel cell according to one embodiment of the invention.

[0034] [Fig. 2] Figure 2 is an exploded perspective view of an electrochemical cell belonging to the fuel cell of Figure 1.

[0035] [Fig. 3] Figure 3 is a front view of a polar plate, showing a primary face, belonging to the fuel cell of Figure 1.

[0036] [Fig. 4] Figure 4 is a view of a detail of figure 3 according to frame IV.

[0037] [Fig. 5] Figure 5 includes a view (a) which is a partial section along the Va-Va line of Figure 4 and a view (b) which is a partial section along the Vb-Vb line of Figure 4.

[0038] [Fig. 6] Figure 6 is a detail view of a polar separator, including the polar plate of Figures 3 and 4, this detail view being analogous to that of Figure 4.

[0039] [Fig. 7] Figure 7 includes a view (a) which is a partial section along line VI la-Vlla of figure 6 and a view (b) which is a partial section along line Vllb-Vllb of figure 6, view (b) being analogous to view (b) of figure 5.

[0040] [Fig. 8] Figure 8 is a detailed view of a bipolar plate including the pole plate of Figure 3. FUEL CELL AND ELECTROCHEMICAL CELLS

[0041] Figure 1 shows a fuel cell 1, comprising a stack 2 of electrochemical cells 4, and two terminal plates 3. The fuel cell 1 is preferentially intended to equip a vehicle, in particular to electrically power an electric motor intended for the traction or propulsion of the vehicle, directly or indirectly (i.e. via a battery).

[0042] Stack 1 defines a longitudinal direction X, a transverse direction Y, and a stacking direction Z. As illustrated, each of these directions X, Y, and Z is oriented, meaning it points in a direction symbolized by an arrow in the figures. These directions are perpendicular to each other and distinct. Preferably, the transverse direction Y points upwards when the stack is in use.

[0043] Stack 2 is interposed between the two end plates 3 along the stacking direction Z and is sandwiched between said end plates 3. Stack 2 is supplied, advantageously via one of the end plates 3, with a primary reactive fluid, a secondary reactive fluid, and preferably a cooling fluid. Each of these fluids is a functional fluid. The primary and secondary reactive fluids react chemically within each cell 4 of stack 2 to generate electricity. The primary and secondary reactive fluids, now laden with reaction products, and the cooling fluid heated by stack 2, are also discharged from stack 2, for example, via the same end plate 3.

[0044] The primary reactive fluid can be an anodic fluid, preferably a hydrogen-containing gas. The secondary reactive fluid can be a cathodic fluid, preferably an oxygen-containing gas, such as air. Alternatively, the primary reactive fluid is the cathodic fluid while the secondary reactive fluid is the anodic fluid. The cooling fluid is advantageously a coolant.

[0045] The stack 2 can include several hundred electrochemical cells 4. As shown in Figure 2, each electrochemical cell 4 comprises, successively along the stacking direction Z, a first polar separator 5, a membrane-electrode assembly 90, and a second polar separator 105.

[0046] Within each cell 4, a chemical reaction occurs between the primary and secondary reactive fluids, creating an electrical potential difference between the first polar separator 5 and the second polar separator 105. Here, for each cell 4, the first polar separator 5 is an anodic separator while the second polar separator 105 is a cathodic separator, but the reverse could be expected. MEMBRANE-ELECTRODE ASSEMBLY 90

[0047] The membrane-electrode assembly 90 has a general plate shape, extending along a plane perpendicular to the stacking direction Z. The membrane-electrode assembly 90 is superimposed with the first polar separator 5 of the same cell 4, along the stacking direction Z; that is, the membrane-electrode assembly 90 and the first polar separator 5 are stacked along the Z direction, specifically with their respective contours overlapping. Thus superimposed, the membrane-electrode assembly 90 is arranged in the stacking direction Z relative to the first polar separator 5. The second polar separator 105 is superimposed with the membrane-electrode assembly 90 of the same cell 4 along the stacking direction Z; that is, the membrane-electrode assembly 90 and the second polar separator 105 are stacked along the Z direction, specifically with their respective contours overlapping.Thus superimposed, the second polar separator 105 is arranged in the stacking direction Z with respect to the membrane-electrode assembly 90 and with respect to the first polar separator 5 of the same cell 4. In other words, for each cell 4, the membrane-electrode assembly 90 is interposed between the first polar separator 5 and the second polar separator 105 along the Z direction. Moreover, the second polar separator 105 of a previous cell 4 of the stacking 2 is superimposed with the first separator 5 of the next cell 4, along the stacking direction Z, and so on.

[0048] The membrane-electrode assembly 90 has a face 91, turned in the opposite direction to the stacking direction Z towards the second immediately adjacent polar separator 5, belonging to the same cell 4. The membrane-electrode assembly 90 has a face 92, turned along the Z direction towards the second immediately adjacent polar separator 105.

[0049] The membrane-electrode assembly 90 comprises a peripheral zone 97 and an exchange zone 93, surrounded by the peripheral zone. Face 91 is formed by the peripheral zone 97 and the exchange zone 93. Face 92 is also formed by the peripheral zone 97 and the exchange zone 93, on the opposite side along the Z direction.

[0050] Preferably, the membrane-electrode assembly 90 is symmetrical in shape around an axis of symmetry parallel to the Z direction.

[0051] The exchange zone 93, also called the active zone, comprises a proton exchange membrane, which is advantageously covered, on the side of face 91, by a gas diffusion layer, and on the side of face 92, by another gas diffusion layer belonging to the exchange zone 93. The membrane is thus interposed between the two gas diffusion layers. Preferably, the entire area of ​​the exchange zone 93, or almost the entire area, is occupied by the proton exchange membrane.

[0052] The peripheral zone 97 forms an outer contour of the assembly 90. The peripheral zone 97 is coplanar with the exchange zone 93, in particular with the membrane, extending in a plane perpendicular to the Z direction.

[0053] The peripheral zone 97 can be made of the same material as the proton exchange membrane, extending the membrane beyond the gas diffusion layers if they are present, so that the peripheral zone 97 is not covered by the gas diffusion layers. Alternatively, the peripheral zone 97 consists of a retaining frame, which surrounds the membrane on its entire perimeter and is assembled with the membrane. The retaining frame is, for example, formed by two superimposed polymer films along the Z-stack direction. The gas diffusion layers, if present, can locally cover the retaining frame, i.e., extend slightly beyond the membrane, at the boundary between the membrane and the retaining frame.

[0054] The membrane-electrode assembly 90 also includes distribution ports 95H, 96H, 950, 960, 950 and 960, provided through the peripheral zone 97. Each port 95H, 96H, 950, 960, 95C and 96C connects face 91 to face 92.

[0055] Port 95H is a feed port belonging to a feed gallery formed through stack 2 along the Z direction and configured to be traversed, along the Z direction, by the primary reactive fluid to feed stack 2. As such, port 95H is itself traversed by the primary reactive fluid. Port 96H is a discharge port belonging to a discharge gallery formed through stack 2 along the Z direction and configured to be traversed, along the Z direction, by a mixture of primary reactive fluid and reaction products from stack 2. As such, port 96H is itself traversed by the mixture. Ports 95H and 96H are located on either side of the exchange zone 93.

[0056] Port 950 is a feed port, belonging to a feed gallery formed through stack 2 along the Z direction and configured to be traversed, along the Z direction, by the secondary reactive fluid to feed stack 2. As such, port 950 is itself traversed by the secondary reactive fluid. Port 960 is a discharge port, belonging to a discharge gallery formed through stack 2 along the Z direction and configured to be traversed, along the Z direction, by a mixture of secondary reactive fluid and reaction products from stack 2. As such, port 960 is itself traversed by the mixture. Ports 950 and 960 are located on either side of the exchange zone 93.Port 95C is a supply port belonging to a supply gallery formed through stack 2 along the Z direction and configured to allow the cooling fluid to flow through it, also along the Z direction, to supply stack 2. As such, port 95C itself is traversed by the cooling fluid. Port 96C is a drain port belonging to a drain gallery formed through stack 2 along the Z direction and configured to allow the cooling fluid from stack 2 to flow through it, also along the Z direction. As such, port 96C itself is traversed by the cooling fluid. Ports 95C and 96C are located on either side of the heat exchange zone 93.

[0057] POLAR SEPARATORS

[0058] The second polar separator 105 comprises a plate face 1110, through which it is superimposed on the membrane-electrode assembly 90, against the face 92, and an opposite plate face 1110. The faces 1110 and 1110 are opposite and perpendicular to the Z direction. The second polar separator 105 includes distribution ports 115H, 116H, 1150, 1160, 1150, and 1160, each distribution port passing through the second separator 105, connecting plate face 1110 to plate face 1110. The ports 115H, 116H, 1150, 1160, 1150, and 1160 are respectively superimposed with the ports 95H, 96H, 950, 960, 950, and 960 of the membrane-electrode assembly 90 along the Z direction, to extend the galleries formed by the ports 95H, 96H, 950, 960, 950, and 960 and be traversed by the same functional fluids.

[0059] The first polar separator 5 is hereafter referred to as polar separator 5. The polar separator 5 comprises a polar plate 10, with a plate face 11 H, rotated along the Z direction and shown in more detail in Figures 3, 4 and 6. The polar plate 10 comprises a plate face 110 opposite to the plate face 11 H.

[0060] The following considerations are developed in relation to the polar separator 5, but preferably also apply to the polar separator 105, which preferably has a design similar to that of the polar separator 5.

[0061] Preferably, the polar separator 5, or at least the polar plate 10, is symmetrical in shape around an axis of symmetry parallel to the Z direction.

[0062] Preferably, the pole plate 10 is formed in one piece from a sheet or plate. The pole plate 10 is advantageously made of an electrically conductive metal, such as titanium or stainless steel, but may alternatively be made of graphite. Preferably, the pole plate 10 is entirely obtained by stamping the sheet or plate. Alternatively, or in addition, the plate 10 may be machined. The plate face 11H extends, overall, along a surface plane P11H, shown in the partial sections of Figures 5 and 7, and is perpendicular to the Z direction. The plate face 11C extends, overall, along a surface plane P11C, shown in the partial sections of Figures 5 and 7, and is perpendicular to the Z direction and parallel to the plane P11H.

[0063] As shown in particular in Figure 2, the polar plate 10 comprises distribution ports 15H, 16H, 15C, 16C, 150 and 160, each distribution port passing through the plate 10, connecting the plate face 11H to the plate face 11C. In particular, each port 15H, 16H, 15C, 16C, 150 and 160 connects a peripheral area 23H belonging to the face 11H to a corresponding peripheral area belonging to the face 11C. Preferably, the ports 15H, 15C and 150 are arranged at one end of the plate 10 along the X direction, while the ports 16H, 16C and 160 are arranged at an opposite end. Port 15C is preferably located between ports 15H and 150, along the Y direction. Port 15H is preferably positioned in the Y direction relative to ports 15C and 150. Port 16C is preferably located between ports 160 and 16H, along the Y direction.Port 160 is preferentially positioned in the Y direction relative to ports 160 and 16H.

[0064] The orifices 15H, 16H, 150, 160, 150 and 160 are respectively superimposed with the orifices 95H, 96H, 950, 960, 950 and 960 of the membrane-electrode assembly 90 along the Z direction.

[0065] Port 15H is a feed port, belonging to the same feed gallery as port 95H. As such, port 15H is itself traversed by the primary reactive fluid. Port 16H is a discharge port, belonging to the same discharge gallery as port 96H. As such, port 16H is itself traversed by the mixture.

[0066] Port 150 is a feed port, belonging to the same feed gallery as port 950. As such, port 150 is itself traversed by the secondary reactive fluid. Port 160 is a discharge port, belonging to the same discharge gallery as port 960. As such, port 160 is itself traversed by the mixture.

[0067] Alternatively, the cathodic fluid, i.e., air, is supplied through port 160, and port 150 is an exhaust port. In other words, ports 150 and 160 can be used interchangeably for supplying or exhausting gases.

[0068] Port 150 is a supply port, belonging to the same gallery as port 950. As such, port 150 itself carries the cooling fluid. Port 16C is a drain port, belonging to the same drain gallery as port 96C. As such, port 16C itself carries the cooling fluid.

[0069] Alternatively, the coolant is supplied via port 16C and port 15C is a drain port. In other words, ports 15C and 16C can be used interchangeably for supplying or draining coolant.

[0070] The polar plate 10 is described here in more detail with regard to the plate face 11H. As shown in figure 2, the plate face 11H is opposite the face 91 of the membrane-electrode assembly 90 of the same cell 4 of the stack 2.

[0071] On the side of the plate face 11 H, the polar plate 10 mainly comprises a circulation field 20H, two conveying fields 21H and 22H, two injection fields 37H and 38H, the aforementioned peripheral zone 23H, a joint 24H and two injection edges 25H and 26H. Advantageously, two anchoring cavity backs 27H and 28H may be provided.

[0072] The peripheral zone 23H is formed directly by the face 11H of the polar plate 10. The peripheral zone 23H encloses the circulation field 20H, the conveying fields 21H and 22H, the injection fields 37H and 38H, and the injection edges 25H and 26H. The peripheral zone 23H has a frame-like shape, forming a closed loop that completely forms a peripheral contour of the face 11H and the plate 10, for example, with a generally rectangular shape.

[0073] The 20H circulation field is preferably arranged in the center of face 11H. Along the X direction, the 20H circulation field is arranged between the 21H and 22H routing fields, located at opposite ends of the 20H circulation field. The 20H field thus connects the 21H and 22H fields.

[0074] Along the X direction, the delivery field 21H is arranged between the circulation field 20H and the ports 15H, 15C, and 150. Along the X direction, the injection field 37H is arranged between the port 15H and the circulation field 20H. In particular, the circulation field 20H begins at one end of the delivery field 21H. The injection field 37H begins at an opposite end of the delivery field 21H. At an opposite end of the injection field 37H, the injection rim 25H, belonging to the peripheral zone 23H, connects the port 15H to the injection field 37H. The injection rim 25H extends to the orifice 15H; that is, the rim 25H delimits the orifice 15H for part of the contour of the orifice 15H. The cavity back 27H is positioned so as to be adjacent to the delivery field 21H and the orifices 15C and 150, being surrounded by the delivery field 21H and the orifices 15C and 150.Symmetrical arrangements to those of the 21H and 37H injection fields apply to the 22H and 38H injection fields. Specifically, along the X direction, the 22H flow field is arranged between the 20H circulation field and the 16H, 16C, and 160 ports. Along the X direction, the 38H injection field is arranged between the 20H circulation field and the 16H port. Specifically, the 20H circulation field terminates at one end of the 22H flow field. The 38H injection field begins at the opposite end of the 22H flow field. At one opposite end of the injection field 38H, the injection rim 26H, belonging to the peripheral zone 23H, connects the delivery field 22H to the orifice 16H. The injection rim 26H extends to the orifice 16H, that is to say, the rim 26H delimits the orifice 16H, for part of the contour of the orifice 16H.The back of cavity 28H is positioned so as to be adjacent to the routing field 22H and to the ports 16C and 160.

[0075] Each injection rim 25H and 26H is preferably formed directly by the face 11H. Preferably, each injection rim 25H and 26H includes a row of injection ports connecting the faces 11H and 11C. Preferably, each injection rim 25H and 26H extends along the plane P11H, at least at the location of the injection ports, and preferably from each injection port to the adjacent injection field 37H or 38H.

[0076] As shown in Figure 3, the injection rim 25H includes injection ports 29HA, for example, arranged in a row extending along the distribution port 15H. Along the X direction, the injection ports 29HA are arranged between the injection field 37H and the port 15H. The injection field 37H is arranged along the row of injection ports. The injection field 37H is arranged between the row of ports 29HA and the delivery port 21H, so as to connect them. Injection ports 29HB of the injection rim 26H are arranged similarly along the distribution port 16H. The injection field 38H thus connects these injection ports to the delivery port 22H.

[0077] The polar separator 5 is configured so that the primary reactive fluid flowing in the orifice 15H is admitted between the face 11H and the face 91 via the injection rim 25H, and then discharged through the orifice 16H via the injection rim 26H. Discharging, the primary reactive fluid flows along the face 11H, successively along the injection rim 25H, the injection field 37H, the conveying field 21H, the circulation field 20H, the conveying field 22H, the injection field 38H and the injection rim 26H.

[0078] Thus, the plate face 11 H is a primary face of the polar plate 10. As it flows along the injection field 37H, the primary reactive fluid divides into several portions of primary fluid, called "injected portions", each guided in parallel by the injection field 37H.

[0079] As it flows along the circulation field 20H, the primary reactive fluid is divided into portions of primary fluid, called "routed portions" of the primary reactive fluid.

[0080] The primary reactive fluid admitted to the surface of the plate face 11 H from the orifice 15H, first flows along the face 11C, from the orifice 15H to the orifices 29HA, then passes through the plate 10 via the orifices 29HA to reach the face 11 H at the injection rim 25H, then to reach the injection field 37H from the injection rim 25H, then the conveying field 21 H from the injection field 37H. The primary reactive fluid to be evacuated from face 11H to orifice 16H, reaches the injection field 38H from the delivery field 22H, then the injection rim 26H, then passes through the injection orifices 29HB of the rim 25H to pass from face 11H to face 11C, then is evacuated through orifice 16H on the side of face 11C.

[0081] POLAR SEPARATOR SEAL

[0082] The seal 24H, shown in dashed lines in Figure 2 and a portion of which is shown in more detail in Figure 6, is received on the plate face 11H, specifically entirely on the peripheral area 23H. The seal 24H is thus a peripheral seal. Preferably, over the entire portion of the peripheral area 23H receiving the seal 24H, said seal 24H is received on a surface of the peripheral area 23H that extends along the surface plane P11H. The seal 24H protrudes from the surface plane P11H in the Z direction. Along the Z direction, the seal 24H comes into contact with the face 91 of the membrane-electrode assembly 90, specifically with the peripheral area 97. The seal 24H thus delimits areas sealed against functional fluids between the faces 11H and 91, preventing said functional fluids from escaping peripherally.

[0083] The 24H seal is preferably formed in one piece. The 24H seal is made of a sealing material, i.e., for example, an elastomer. The 24H seal is preferably obtained by overmolding said 24H seal directly onto face 11H, or alternatively onto face 91. Alternatively, the 24H seal can be manufactured separately and then attached to face 11H, or alternatively to face 91.

[0084] The 24H seal includes a main closed loop 31H, formed on face 11H, or at least interposed between face 11H and face 91. The main closed loop 31H serves to keep the primary reactive fluid circulating along face 11H within the main closed loop 31H, between faces 11H and 91. On the side of face 11H, the main closed loop 31H surrounds at least the circulation field 20H, the injection fields 37H and 38H, and the delivery fields 21H and 22H. On the side of face 91, the closed loop surrounds the exchange zone 93.

[0085] It is advantageously provided that the orifices 15H, 15C, 150, 16H, 160 and 160 are arranged outside the main closed loop 31 H, as shown in Figure 2, insofar as the injection rims 25H and 26H have injection orifices such as the orifices 29HA, 29HB. Similarly, ports 95H, 950, 950, 96H, 960, and 960 are arranged outside the main closed loop 31H. Furthermore, the injection ports of the injection rims 25H and 26H, specifically injection ports 29HA and 29HB, are located inside the main closed loop 31H. Consequently, all the primary reactive fluid circulating on the surface of face 11H is enclosed within the main closed loop 31H, preventing said primary reactive fluid from escaping around the periphery of face 11H. Thus, seal 24H contains the primary reactive fluid on the surface of face 11H.

[0086] Preferably, the 24H seal comprises secondary closed loops, shown as dashed lines in Figure 2, each surrounding one of the distribution ports and being received on the plate face 11H. Each secondary closed loop contacts the face 91 along the Z direction, so as to be interposed between the face 11H and the face 91. Preferably, each secondary loop is formed as a single unit with the main closed loop 31H. Preferably, each port 15H, 15C, 150, 16H, 16C, and 160 is surrounded by a respective secondary closed loop belonging to the 24H seal. Since each secondary loop is also in contact with the face 91, each port 95H, 95C, 950, 96H, 96C, and 960 is also surrounded by one of the respective secondary loops. Each secondary loop therefore connects, along the Z direction, one of the orifices 15H, 15C, 150, 16H, 16C and 160 to the orifice 95H, 95C, 950, 96H, 96C or 960 which is superimposed on it, to form the corresponding gallery.Each secondary loop thus ensures that the functional fluid circulating in the gallery concerned does not escape out of cell 4, nor into the interior of the main closed loop 31 H, except in the presence of one of the injection rims, as is the case for orifices 15H and 16H.

[0087] Preferably, no part of the 24H seal subdivides the closed loop(s) into several closed loops formed by the 24H seal.

[0088] POLAR SEPARATOR FIELD OF CIRCULATION

[0089] Preferably, the traffic area 20H is formed directly by the plate face 11H. Preferably, the traffic area 20H has a generally rectangular shape along the X and Y directions. The traffic area 20H includes walls 40, which are raised along the Z direction relative to the surface plane P11H. Preferably, each wall 40 of the traffic area 20H connects the two ends of the traffic area 20H along the X direction, that is, it extends from area 21H to area 22H. The walls are arranged side-by-side so as to delimit channels 42 between them, each channel 40 being located between two successive walls 42. Between two successive walls 42, the channel 40 is delimited by a channel bottom formed by the face 11H. Each channel connects area 21H to area 22H. Preferably, the traffic area 20H is formed by stamping the plate 10, the stamping allowing the walls 40 and the channels 42 to be obtained in relief.

[0090] Following the Z direction, the circulation field 20H, in particular each wall 40, comes to rest against the exchange zone 93 of the membrane-electrode assembly 90, being superimposed with the exchange zone 93. Preferably, the circulation field 20H is in rest against the exchange zone 93 over its entire surface, or the exchange zone 93 is in rest against the circulation field 20H over its entire surface.

[0091] The primary reactive fluid flowing along face 11H is admitted along circulation field 20H from delivery field 21H and flows to the opposite end of circulation field 20H via channels 42 of said circulation field 20H, being guided by said channels and distributed over said channels. At the opposite end of circulation field 20H, the primary reactive fluid is admitted into delivery field 22H. During its flow along field 20H, the primary reactive fluid comes into contact with the exchange zone 93, where the reaction occurs across the proton exchange membrane, generating an electrical potential difference between separators 5 and 105.

[0092] Parallel to the transverse direction Y, the traffic area 20H is delimited by two final walls 41 belonging to the walls 40, the last two walls 41 being respectively located at the two transverse ends of the traffic area. In other words, along the transverse direction Y and opposite to the transverse direction Y, the traffic area 20H terminates at the level of a final wall 41.

[0093] Preferably, as in the example shown in the figures, the walls 40 and, consequently, the channels 42, do not extend in a straight line along the longitudinal direction X, but meander, undulate, that is to say, they are curved. In other words, each wall 40 and each channel 42 extends approximately along the longitudinal direction X, but is curved alternately along the transverse direction Y and then in the opposite direction. We thus denote D40 as a periodicity of the undulation of the walls 40 and consequently of the channels 42, the periodicity D40 corresponding to a distance, measured along the longitudinal direction X, between two consecutive maxima of the walls 40, that is to say, between two troughs, or two crests, of the oscillations of the walls 40.In the example, the polar plate 10 has a thickness H 10, measured between the surface plane P11H and the surface plane P11C parallel to the stacking direction Z, of between 0.05 mm and 0.10 mm, preferably equal to 0.075 mm.

[0094] In the example, each wall 40 has a height H40, measured along the stacking direction Z from the surface plane P11H, of between 0 mm and 0.35 mm, preferably equal to 0.12 mm. Furthermore, in the example, each channel 42 has a height H42A, measured opposite the stacking direction Z between the surface plane P11H and the face 11H at the channel level, of between 0 mm and 0.35 mm, preferably equal to 0.08 mm. The height H42A of the channels 42 is also referred to as the channel depth, since the channels 42 are recessed relative to the plate face 11H.In practice, when the height H40 is equal to 0 mm, it is understood that the channels 42 are formed only in hollows relative to the surface plane P11H, but that, within the circulation field 20H, there is still an alternation between hollows and bumps, that is to say between channels and walls, the walls then corresponding to the parts of the circulation field 20H located at the level of the surface plane P11H, according to the stacking direction Z, and the channels corresponding to the parts formed in hollows relative to the surface plane P11H.

[0095] Furthermore, the height of the channels 42 can also be measured between the bottom of the channels 42, i.e., the face of plate 11H at the channel level, and the top of the walls 40, i.e., the face of plate 11H at the wall level. This height, denoted H42B, is in this example between 0.1 mm and 0.35 mm, preferably equal to 0.20 mm. In practice, the height H42B is preferred for quantifying the height of the channels 42.

[0096] Furthermore, in the example, a height H42C, measured parallel to the stacking direction Z between the plate face 11H at the level of the walls 40 and the plate face 11C at the level of the channels 42, is in the example between 0.15 mm and 0.45 mm, preferably equal to 0.275 mm. In practice, the height H42C is preferred for quantifying the thickness of the polar plate 10 and the cell 4.

[0097] As can be seen in Figure 5, the walls 40 do not extend along the stacking direction Z, but obliquely to the stacking direction Z. Thus, the walls 40 and the channels 42 are alternated by defining a repeated wavy pattern, allowing a simplified manufacture of the polar plate 10, in particular by stamping.

[0098] Preferably, a width L43 of the repeating pattern of the walls 40 and channels 42 is between 0.50 mm and 1.5 mm, for example equal to 0.90 mm, this width corresponding to the distance between the bottom of two successive channels 42. Preferably, a width L40 of each wall 40, measured along the transverse direction Y at the top of the wall, is between 0.05 mm and 0.35 mm, preferably also equal to 0.15 mm.

[0099] Preferably, a width L42A of each channel 42, measured along the transverse direction Y at the bottom of the channel, is between 0.05 mm and 0.35 mm, preferably still equal to 0.15 mm.

[0100] Furthermore, a width L42B of each channel 42, measured along the transverse direction Y between the tops of the two walls 40 delimiting the channel, is between 0.35 mm and 1.25 mm, preferably equal to 0.75 mm. In the example, the channels 42 have a constant width. Alternatively, this width can vary, the values ​​indicated then being applicable to the largest width of the channels 42.

[0101] BYPASS ZONE

[0102] The polar plate 10 comprises two rims 50, formed by the plate face 11 H and extending the polar plate 10 beyond the circulation field 20H, parallel to the transverse direction Y, on either side of the circulation field. Thus, the two rims 50 are part of the peripheral zone 23H. These two rims 50 are located at the level of the circulation field 20H, along the longitudinal direction X. The last walls 41 border the circulation field 20H, and therefore border the rims 50, so that the last walls 41 prevent the flow of the primary reactive fluid from the circulation field 20H to the rims 50.

[0103] Preferably, a width L50 of the edge 50, measured parallel to the transverse direction Y between the last wall 41 and one end of the edge 50, is between 5 mm and 15 mm, preferably 10 mm. In practice, since the last wall 41 does not extend in a straight line but is undulating, the width L50 of the edge 50 varies along the longitudinal direction X. Thus, the values ​​given as examples correspond to the smallest width L50, that is, the width of the edge 50 when the last wall 41 is closest to the end of the edge 50.

[0104] The joint 24H forms a closed loop surrounding the traffic area 20H. Longitudinal portions 52 of the joint 24H are arranged on the two edges 50, on either side of the traffic area 20H. A portion of one of these longitudinal portions 50 of the joint 24H is visible in Figure 6. Since the joint 24H surrounds the traffic area 20H, these longitudinal portions 52 extend over the entire length of the traffic area 20H, measured along the longitudinal direction X and denoted L20H.

[0105] Preferably, the longitudinal portions 52 of the 24H joint are directly attached to the plate face 11H of the polar plate 10, as seen in Figure 7. Figure 7 also shows part of a 24C joint, which is comparable to the 24H joint and is arranged on the plate face 11C of the polar plate 10.

[0106] In the example, the longitudinal portion of joint 52 has a width L52, measured parallel to the transverse direction Y, of between 0.5 mm and 4 mm, for example equal to 1.8 mm.

[0107] In practice, for each rim 50, the longitudinal portion 52 of the seal 24H is received on a lateral sealing location 54 formed by the rim 50 of the polar plate 10. In other words, the polar plate includes two lateral sealing locations 54, arranged on either side of the circulation field 20H parallel to the transverse direction Y and intended to receive the longitudinal portions 52 of the seal 24H.

[0108] It is noted that the joint 24H is located at a distance from the last wall 41. Therefore, on the plate face 11H of the polar plate 10, part of the reactive fluid circulating from the distribution orifice 15H to the distribution orifice 16H is likely to bypass the circulation field 20H, by circulating along the edges 50, between the circulation field 20H and the peripheral joint 24H, more precisely between the last wall 41 and the longitudinal portion 52 of the joint 24H.

[0109] A bypass zone 56 is thus defined as the area formed between the last wall 41 and the longitudinal portion 52 of the peripheral joint 24H. The bypass zone 56 therefore allows the flow of primary reactive fluid from the inlet orifice 15H to the outlet orifice 16H, bypassing the circulation field 20H. On the side of the plate face 11H, the polar plate 10 then comprises two bypass zones 56, arranged on either side of the circulation field 20H along the transverse direction Y. The bypass zones 56 can also be referred to as "bypass zones".

[0110] Each bypass zone 56 has a width L56, measured between the last wall 41 and the longitudinal portion 52 of the joint 24H parallel to the transverse direction Y, which is preferably between 3 mm and 10 mm, and preferably 7 mm. The width L56 can also be measured between the last wall 41 and the lateral sealing location 54. In practice, since the last wall 41 does not extend in a straight line but is corrugated, the width L56 of the bypass zone 56 varies along the longitudinal direction X. Thus, the values ​​given as examples correspond to the smallest width L56, i.e., the width of the bypass zone 56 when the last wall 41 is closest to the longitudinal portion 52 of the joint 24H. By definition, the width L56 of the bypass zone is less than the width L50 of the rim 50.Advantageously, a ratio of the smallest width L56 of the bypass zone 56 to a larger width L42B of the channels 42 is greater than 2.5, preferably greater than 4, preferably even greater than 6, in the example equal to 8.

[0111] Advantageously but optionally, the polar separator 5 includes several slowing fins 58, which are formed from the material with the peripheral seal 24H, more precisely which are formed from the material with the longitudinal portions 52. Preferably, the slowing fins 58 are obtained by overmolding, simultaneously with the peripheral seal 24H.

[0112] As can be seen in Figure 6, the retarding fins 58 are arranged on the rim 50, in the bypass area 56.

[0113] The decelerating fins 58 are intended to limit the amount of primary reactive fluid that bypasses the circulation field 20H and would flow into the bypass zones 56. As more clearly seen in Figure 7, the decelerating fins 58 protrude from the plate face 11H, along the stacking direction Z, from the rim 50. Thus, the decelerating fins form obstacles opposing the flow of primary reactive fluid in the bypass zone 56.

[0114] Preferably, along the longitudinal direction X, the deceleration fins 58 are regularly spaced along the rim 50. For example, a distance D58 between two consecutive deceleration fins 58, measured parallel to the longitudinal direction X, is between 10 mm and 40 mm, preferably still equal to 20 mm.

[0115] Each speed-reducing fin 58 extends from the longitudinal portion 52 of the peripheral joint 24H towards the traffic area 20H and the last wall 41. Thus, each speed-reducing fin 58 is entirely located in the bypass area 56.

[0116] In the example, each braking fin 58 is angled, having a first part 58A extending from the joint 24H parallel to the transverse direction Y, and then a second part 58B extending from the end of the first part 58A obliquely to the transverse direction Y, that is, extending partly along the transverse direction Y and partly along the longitudinal direction X. For example, the angle of a straight line between the first part 58A and the second part 58B can be expected to form an angle of approximately 30 to 75 degrees with respect to the longitudinal direction X.

[0117] In an unrepresented variant of the invention, each slowing fin 58 is straight and extends from the longitudinal portion 52 of the peripheral joint 24H towards the last wall 41 either parallel to the transverse direction Y, or obliquely with respect to the transverse direction Y. According to another unrepresented variant, each cooling fin 58 is hook-shaped.

[0118] Each decelerating fin 58 is arranged so that its end is as close as possible to the last wall 41, so as to effectively limit the flow of primary reactive fluid in the bypass zone 56. However, in order for the decelerating fins 58 to be easily manufactured, in particular by overmolding simultaneously with the joint 24H, each decelerating fin is distant from the last wall 41, in particular along the transverse direction Y.

[0119] In a particularly advantageous manner, and as can be seen in Figure 6, the distance D58 between two consecutive decelerating fins 58 is equal to the periodicity D40 of the walls 40 and the channels 42. Preferably, each decelerating fin 58 is arranged so that its free end is located opposite a hollow of the last wall 41, as can be seen in Figure 6. Thus, since the decelerating fins 58 extend towards the hollows of the last wall 41, their length can be greater than if the fins extended towards the humps of the last wall. Therefore, the deceleration fins 58 are more effective in limiting the flow of primary reactive fluid in the bypass zone 56. By "hollow" and "bump" of the last wall 41, we mean here respectively the parts of the last wall which are furthest and closest to the rim 50 and the deceleration fins 58, along the transverse direction Y.

[0120] It is noted that, in the example, the decelerating fins 58 are arranged obliquely, with the decelerating fins advancing along the longitudinal direction X away from the peripheral joint 24H. This inclination of the decelerating fins 58 generates turbulence in the flow of the primary reactive fluid after the passage of each fin, thus reinforcing the deceleration of this flow.

[0121] Preferably, each fin has a width L58, measured perpendicular to the main direction of the fin, for example along the longitudinal direction for the first part 58A, which is preferably between 1 mm and 5 mm, preferably still equal to 2 mm.

[0122] RIGIDIFICATION OF THE BYPASS ZONE

[0123] To stiffen the rim 50, and in particular the bypass zone 56, the polar plate 10 has a stiffening relief 60, formed by the plate face 11H on the rim 50, between the last wall 41 and the lateral sealing location 54, in the transverse direction, i.e., between the last wall 41 and the longitudinal portion 52 of the peripheral joint 24H. The stiffening relief 60 is thus located in the bypass zone 56. Consequently, the bypass zone 56, traditionally particularly prone to deformation because it is located at the edge of the polar plate 10, has its stiffness remarkably improved thanks to the stiffening relief 60.

[0124] The stiffening relief 60 preferably has a constant width L60A, measured along the transverse direction Y, of between 0.30 mm and 2 mm, preferably equal to 0.70 mm. The width L60A is thus of the same order of magnitude as the width L42B of the channels 42.

[0125] The stiffening relief 60 preferably has a height H60, or depth H60, measured parallel to the stacking direction Z between the surface plane P11H and the face 11H at the level of the stiffening relief 60, of between 0.05 mm and 0.3 mm, preferably also equal to 0.09 mm. The depth H60 is thus of the same order of magnitude as the height H42A of the channels 42, or even equal to the depth H42A of the channels.

[0126] In a particularly advantageous way, the height H60 of the stiffening relief 60 is less than or equal to the height H42A of the channels 42 and to the height H40 of the walls 40. Thus, the stiffening relief 60 does not increase the bulk of the polar plate 10, parallel to the stacking direction Z.

[0127] The stiffening relief 60 extends over at least 75% of the length L20H of the traffic lane 20H, along the longitudinal direction X, preferably over at least 90% of the length L20H, and preferably over at least 100% of the length L20H. In the example, the stiffening relief 60 extends over 103% of the length L20H, meaning that the stiffening relief 60 extends on both sides of the traffic lane 20H, parallel to the longitudinal direction X. In other words, a length L60B of the stiffening relief 60 is greater than the length L20H of the traffic lane 20H. This effectively stiffens the bypass area 56, including beyond the traffic lane 20H.

[0128] Regardless of its length, the stiffening relief 60 is aligned with the traffic area 20H, parallel to the longitudinal direction X; that is, it is located at the level of the traffic area. Thus, the two stiffening reliefs 60 are located on either side of the traffic area 20H.

[0129] Preferably, the stiffening relief 60 extends continuously along the entire length L60B, i.e., the stiffening relief is uninterrupted. In the example, the stiffening relief 60 is straight and extends parallel to the longitudinal direction X. In an alternative not shown, the stiffening relief 60 is not straight but extends, for example, in a meandering pattern within the bypass zone 56, in a wavy fashion, or in a sawtooth pattern. Preferably, a smaller distance D60 between the stiffening relief 60 and the last wall 41, measured along the transverse direction Y, is greater than 2 mm, preferably greater than 5 mm.

[0130] In the example, the stiffening relief 60 forms a recess relative to the plate face 11H; that is, the stiffening relief extends from the surface plane P11H in the opposite direction to the stacking direction Z, towards the surface plane P11C. The stiffening relief 60 is thus comparable to a stiffening groove formed on the plate face 11H. This recessed arrangement of the stiffening relief 60 is advantageous for allowing the damping fins 58 to be superimposed on the stiffening relief 60. Thus, the damping fins 58 extend from the peripheral joint 24H towards the traffic area 20H, crossing, or passing through, the stiffening reliefs 60.

[0131] In addition, the polar separator 5 also includes two filling joints 62, one of which is visible in Figure 7, each filling joint 62 filling, or filling, one of the two stiffening reliefs 60, so that the filling joint 62 is flush with the plate face 11 H, i.e. so that the surface of the filling joint 26 is disposed at the level of the surface plane P11H, according to the stacking direction Z.

[0132] It is particularly advantageous for each filling joint 62 to fill one of the two stiffening reliefs 60, being flush with the plate face 11 H, because in this way the filling joint 62 does not protrude from the stiffening relief and, consequently, does not impede the flow of reactive fluid in the bypass zone 56. Thus, the filling joints 62 do not affect the operation of the bypass zone 56. Therefore, thanks to the filling joints 26, the stiffening reliefs 60 also do not affect the operation of the bypass zone 56.

[0133] Preferably, the filling seals 62 are made of the same material as the peripheral seal 24H and the slowing fins 58, so that the filling seals 62, the peripheral seal 24H and the slowing fins 58 are applied simultaneously and in a single operation to the pole plate 10. This makes it possible to form a gasket material assembly which is sufficiently strong to withstand the various mechanical stresses applied during the stacking of the plates 10, and easy to produce, in particular by a single overmolding step on the plate 10.

[0134] In an unshown embodiment of the invention, the stiffening relief 60 forms a bump relative to the plate face 11H, i.e., the stiffening relief extends from the surface plane P11H along the stacking direction Z, opposite the surface plane P11C. The stiffening relief then forms a stiffening rib. In such an embodiment, since the stiffening relief 60 forms a depression relative to the plate face 11C, the filler joint 62 is disposed on the plate face 11C inside the stiffening relief, so as to be flush with the surface plane P11C. Alternatively, in such an embodiment, the polar separator 5 does not have a filler joint 62.

[0135] The stiffening relief 60 is particularly advantageous for stiffening the polar plate 10 at the bypass zone 56, especially along the transverse direction Y. Thus, the stiffening relief 60 makes it possible to limit the deformations of the polar plate 10 at the bypass zone 56. This makes it possible in particular to minimize, if not eliminate, any risk of deformation of the plate 10 in the boundary zone 50, a traditionally fragile area, and thus in particular the risk of short circuit by accidental contact between two polar plates 10 of opposite polarities.

[0136] The fact that the stiffening relief 60 is located in the bypass zone 56 is particularly advantageous, as this position maximizes the stiffening of the polar plate 10 at the bypass zone 56 and is easy to implement, as the bypass zone has a width L56 sufficient to easily position the stiffening relief 60.

[0137] According to embodiments of the invention, the polar plate 10 also includes, in addition to or instead of the stiffening relief, groups 64 of stiffening reliefs.

[0138] The groups 64 all include at least two stiffening reliefs formed by the plate face 11H on the rim 50, between the last wall 41 and the lateral sealing location 54, along the transverse direction Y, the stiffening reliefs being thus arranged in the bypass zone 56.

[0139] In the example, each group 64 comprises three stiffening reliefs, noted respectively as 66, 68 and 70.

[0140] In the example, in each group 64, the stiffening relief 66, called the first stiffening relief, is adjacent to the stiffening relief 68, which is itself adjacent to the stiffening relief 70, called the last stiffening relief. Therefore, the stiffening relief 68, then called the central stiffening relief, is interlocked with both the first and last stiffening reliefs 66 and 70. Furthermore, since the first and last stiffening reliefs 66 and 70 are separated from each other by the central stiffening relief 68, they are not interlocked. In other words, the stiffening reliefs 66, 68, and 70 are interlocked in pairs.

[0141] Within each group 64, the stiffening ridges are nested, that is, interlocked with each other, in the longitudinal direction X and in the transverse direction Y. This allows the bypass zone 56 to be stiffened in both the transverse direction Y and the longitudinal direction X, as well as in any other oblique direction. In other words, within each group and for two nested stiffening ridges, each stiffening ridge has at least two non-parallel edges, each of these two edges being parallel to and opposite one edge of the other of the two nested stiffening ridges. In other words, as can be seen in particular in Figure 6, the stiffening ridges 66, 68, and 70, within the same group 64, exhibit complementary geometric shapes.More specifically, in the case where group 64 comprises three stiffening reliefs, the first stiffening relief 66 has a geometric shape that is at least partly complementary to the geometric shape of the central stiffening relief 68. The last stiffening relief 70 has a geometric shape that is at least partly complementary to the geometric shape of the central stiffening relief 68.

[0142] Thanks to the interlocking of the stiffening ridges in each group 64, there is no axis within a group 64 that lies in the surface plane P11 H and can pass through the group 64 without intersecting at least one stiffening ridge 66, 68, or 70. In other words, there is no straight line extending between the stiffening ridges of the same group and passing completely through said group. Consequently, within a group 64, there is no fold line, meaning there is no preferred direction of deformation, so the groups 64 are particularly effective at stiffening the bypass zone 56.

[0143] Thus, in the example, the stiffening relief 66 has a first edge 66A and a second edge 66B, the stiffening relief 68 has a first edge 68A, a second edge 68B, a third edge 68C, and a fourth edge 68D, and the stiffening relief 70 has a first edge 70A and a second edge 70B. Furthermore, the first edge 66A is parallel to the first edge 68A, and the second edge 66B is parallel to the second edge 68B, so that the stiffening relief 66 and the stiffening relief 68 are nested. Moreover, the first edge 70A is parallel to the third edge 68C, and the second edge 70B is parallel to the fourth edge 68D, so that the stiffening relief 70 and the stiffening relief 68 are nested.

[0144] Thus, the stiffening reliefs 66, 68, and 70 have complex shapes, allowing them to be nested. For example, stiffening reliefs 66 and 70 are concave irregular hexagons, and stiffening relief 68 is a concave irregular octagon, with rounded vertices. For example, the central stiffening relief 68 is roughly T-shaped. In general, it is advantageous for stiffening reliefs 66, 68, and 70 to each have a concave irregular polygon shape with at least six sides, preferably with rounded vertices.

[0145] In another example, each stiffening relief 66, 68, and 70 has at least one curved, or rounded, edge facing a curved edge of another of the stiffening reliefs 66, 68, and 70. In such an example, the stiffening reliefs 66, 68, and 70 have complex shapes that allow them to be nested but are not polygons. For simplicity, two facing curved edges are said to be parallel.

[0146] In general, each stiffening relief 66, 68, 70 has at least one convex portion received in a concave portion of another of the stiffening reliefs 66, 68, 70. It is then understood that, for two juxtaposed stiffening reliefs 66 and 68 or 68 and 70, each relief has an outgrowth received in a pocket, or a recess, of the other relief, thus contributing to the imbrication of the reliefs with each other.

[0147] Furthermore, within each group 64, the stiffening ridges 66, 68, and 70 preferably all have a different shape. Generally, it is advantageous for at least two stiffening ridges within the same group 64 to have a different shape. In a non-shown embodiment of the invention, all the stiffening ridges within the same group have the same shape, which is a complex shape allowing the stiffening ridges to be nested among themselves, such as, for example, an irregular concave polygon with at least six sides, or even seven or eight sides, or more. This notably improves the bending resistance of the bypass zone 56 since no symmetry can be established within a group 64 of ridges 66, 68, and 70.

[0148] Such forms of stiffening reliefs 66, 68, 70 and such an interlocking, allow, in a quite remarkable way, the maximization of the bulk of the stiffening reliefs to the stiffening of the plate 10. In other words, it is possible to considerably increase the stiffness of the rim 50 of the plate, without increasing the size of the latter.

[0149] Furthermore, within a group 64, the stiffening reliefs 66, 68, and 70 are not superimposed; that is, they do not overlap, and no stiffening relief lies within the contour of another stiffening relief. In other words, no stiffening relief 66, 68, or 70 is located inside another stiffening relief 66, 68, or 70.

[0150] In the example, the 64 groups are identical to each other.

[0151] Preferably, a width L64A of the groups 64, i.e., of the stiffening reliefs 66, 68, and 70, measured parallel to the transverse direction Y, is between 3.0 mm and 6.0 mm, preferably even greater than 4.0 mm. Thus, the width of the groups 64 is significantly greater than the width L42B of the channels 42, in particular at least four times greater than the width L42B, in the example approximately eight times greater.

[0152] Furthermore, the groups 64 are advantageously arranged between the stiffening relief 60 and the last wall 41, along the transverse direction Y. Moreover, a small distance E64 between the groups 64 and the last wall 41, measured along the transverse direction Y, is preferably greater than or equal to twice the width L42B of the channels 42. Thus, the groups 64 are arranged at a distance from the channels 42. In practice, it is not necessary to place the groups 64 in the immediate vicinity of the channels 42, because, in the traffic area 20H and in the immediate vicinity of the traffic area, the stiffness of the polar plate 10 is already ensured by the alternation of the walls 40 and the channels 40.

[0153] Furthermore, the groups 64 are advantageously located at a distance from the stiffening relief 60, along the transverse direction Y.

[0154] Preferably, a length L64B of each group 64, measured along the transverse direction X at the center of the group, along the transverse direction Y, is between 8 mm and 18 mm, preferably equal to 13 mm. By "at the center of the group along the transverse direction Y" we preferably mean dividing the total width of the group along the transverse direction Y by two, in order to draw an imaginary line separating the group in two along the transverse direction Y, so as to be able to measure the length of said imaginary line along the longitudinal direction X between the two points of intersection between the beginning and the end of the group of motifs and said imaginary line, as can be seen in figure 4 for example.

[0155] The groups 64 are all aligned with each other and spaced, along the longitudinal direction X. In the example, two consecutive groups 64 are separated by a distance L74A, measured parallel to the longitudinal direction X, of between 1 mm and 5 mm, preferably still equal to 3 mm.

[0156] A spacing location 74 is thus defined, formed by the rim 50 between two consecutive groups 64, delimited along the longitudinal direction X by said two groups 64 and delimited along the transverse direction Y by the first wall 41 and by the longitudinal portion 52 of the peripheral joint 24H, i.e. by the lateral sealing location 54. A width of the spacing location 74, measured parallel to the longitudinal direction X, is thus equal to L74A.

[0157] As shown in Figure 6, the speed-reducing fins 58 extend advantageously into the spacing locations 74. In other words, a speed-reducing fin 58 is positioned between, or separates, two consecutive groups 64 of stiffening ridges. This allows for optimal use of all available space in the bypass zone 56, and for the regular grouping and alternation of the functions of stiffening the bypass zone 56 and limiting the flow within it. Therefore, it is advantageous for the groups 64 to be arranged between the stiffening ridge 60 and the last retaining wall 41, along the transverse direction Y: this arrangement allows for the stiffening of the bypass zone 56 between the spacing locations 74, in a manner complementary to the stiffening ridge 60.More specifically, the stiffening relief 60, by virtue of its longitudinal character, makes it possible to stiffen the bypass zone 56 and the rim 50 of the plate 10 in a longitudinal direction, while the stiffening reliefs 66, 68, 70 make it possible to stiffen the bypass zone 56 in the longitudinal and transverse directions.

[0158] Thus, the spacers 74 advantageously have a profile comparable to that of the speed-reducing fins 58, i.e., in the example, an oblique profile. In other words, the spacers 74 extend obliquely from the longitudinal portion 52 of the perimeter joint 24H towards the last wall 41. A width L74B of the spacers 74, measured perpendicular to the second part 58B of the speed-reducing fins 58 and in the surface plane P11H, is preferably between 1 mm and 5 mm, preferably even more so 3 mm, the width L74B being greater than the width L58 of the speed-reducing fins 58.

[0159] Furthermore, as illustrated in Figure 4, since the spacing locations 74 extend obliquely, it is understood that a longitudinal length L64C of each group 64, measured along the longitudinal direction X between two extremity points of the group, is greater than the length L64B of each group. In the example, this length L64C is between 10 mm and 30 mm, preferably equal to 16 mm.

[0160] Advantageously, the length L64B of each group 64 is between two and six times the width L74A of the spacing location.

[0161] Since the polar separator 105 of a preceding cell 4 of the stack 2 is superimposed with the separator 5 of the following cell 4, along the stacking direction Z, and since the polar separator 105 advantageously has a design similar to the polar separator 5, including the bypass zone 56, the stiffening relief 60, and the groups 64 of stiffening reliefs 66, 68, and 70, then it is advantageous for the length L64B of each group 64 to be greater than or equal to twice the width L74A of the spacing location. Indeed, this allows that, for a superimposed polar separator 105 and polar separator 5, each group 64 of the polar separator 5 overlaps one of the spacing locations 74 of the separator 105 by extending beyond said spacing location on both sides, so as to also partially overlap the two groups 64 delimiting said spacing location, and vice versa.In other words, when polar separator 105 and polar separator 5 are superimposed, the spacing locations 74 of one polar separator are "filled" by a group 64 of stiffening reliefs from the other polar separator. Thus, when a polar separator 105 and a polar separator 5 are superimposed, forming a plate or a bipolar separator, the groups 64 of the two polar separators stiffen the polar plates of the polar separators, including at the spacing locations, thereby improving the stiffness of the entire bipolar separator assembly.

[0162] It is advantageous that the length L64B of each group 64 be less than or equal to five times the width L74A of the spacing location, because in this way the width L74A is sufficiently large in view of the length L64B of the groups 64 to place a deceleration fin 58 between two groups 64, without interfering with the groups 64.

[0163] Particularly advantageously, and as can be seen in Figure 6, a distance D64 between the same point of two consecutive groups 64, that is to say a periodicity of repetition of the groups 64, measured parallel to the longitudinal axis X, is equal to the periodicity D40 of the walls 40 and the channels 42. Thus, the distance D64 is also equal to the distance D58. Therefore, the groups 64 are regularly spaced and arranged between the deceleration fins 58. Furthermore, since the deceleration fins 58 are arranged so that their free ends are located opposite the hollows of the last wall 41, then the groups are centered with the bumps of the last wall 41, as seen in Figure 4. It is thus understood that the distance D64 is determined as a function of the periodicity D40 of the walls 40 and the distance D64 and that the length L64B of the groups 64 is a function of the distance D64 and the width L58 of the deceleration fins 58.

[0164] This particular arrangement of the slowing fins 58 and the groups 64 is particularly advantageous for simultaneously optimizing the slowing of the reactive fluid flow passing through the bypass zone 56 thanks to the arrangement of the slowing fins 58, and optimizing the stiffening of the bypass zone 56 and the rim 50, by using all the available space between the slowing fins to form the groups 64.

[0165] In the example, the stiffening ridges 66, 68, and 70 of each group 64 form hollows with respect to the plate face 11H; that is, the stiffening ridges 66, 68, and 70 extend from the surface plane P11H in the opposite direction to the stacking direction Z, towards the surface plane P11C. Thus, the stiffening ridges 66, 68, and 70 extend in the same direction, along the stacking axis Z, as the stiffening ridge 60 described previously. In a non-shown variant of the invention, the stiffening ridges 66, 68, and 70 form bumps relative to the plate face 11H; that is, they extend from the surface plane P11H along the stacking direction Z, opposite the surface plane P11C. According to another variant, some of the stiffening ridges 66, 68, and 70 form hollows and others form bumps.

[0166] The stiffening ridges 66, 68, and 70 of the groups 64 preferably have a height H64, or depth H64, measured parallel to the stacking direction Z between the surface plane P11 H and the face 11 H at the stiffening ridges 66, 68, and 70, of between 0.05 mm and 0.3 mm, preferably also equal to 0.09 mm. The depth H66 is thus of the same order of magnitude as the height H42A of the channels 42, or even equal to the depth H42A of the channels. In this case, as illustrated, each of the first, last ridges 66, 70, and central ridge 68 has approximately the same height. However, one could imagine a variant in which each of the ridges 66, 68, and 70 would have a different height.

[0167] In a particularly advantageous way, the height H64 of the stiffening reliefs 66, 68 and 70 of the groups 64 is less than or equal to the height H42A of the channels 42 and to the height H40 of the walls 40. Thus, the stiffening reliefs 66, 68 and 70 of the groups 64 do not increase the bulk of the polar plate 10, parallel to the stacking direction Z.

[0168] Preferably, the height H64 of the stiffening reliefs 66, 68, 70 is substantially equal to the height H60 of the stiffening relief 60.

[0169] The presence of the stiffening relief 60 and / or the groups 64 of stiffening reliefs 66, 68, 70 in the bypass zone 56 is particularly advantageous for stiffening the polar plate 10 in an area where the plate is usually not very rigid and where increasing its rigidity is most beneficial. Indeed, at the circulation field 20H, the polar plate already exhibits satisfactory rigidity thanks to the alternating walls 40 and channels 40. Conversely, at the edges 50, the rigidity of the polar plate is generally insufficient to prevent deformations, which are avoided by the invention. It is all the more important to prevent any accidental deformation of the plate 10 towards its edge, as this is an area prone to damage during the handling and / or stacking of the polar plate 10.Such a deformation can in particular result in a risk of short circuit, for example if two edges 50 of two plates 10 of opposite polarities accidentally came into contact.

[0170] Furthermore, the bypass zone 56 advantageously has a width L56 sufficient to accommodate the stiffening relief 60 and / or the groups 64 of stiffening reliefs 66, 68, 70. Thus, the addition of the stiffening relief 60 and / or the groups 64 of stiffening reliefs 66, 68, 70 does not impact the overall design of the polar plate 10. The stiffening relief 60, by extending continuously over at least 75% of the length of the traffic field 20H, is particularly effective in stiffening the polar plate 10 by preventing deformations of the polar plate along bending axes perpendicular or oblique to the longitudinal direction X.

[0171] In addition, the groups 64 of stiffening reliefs 66, 68, 70, by presenting complex and interlocking stiffening reliefs, are particularly effective in stiffening the polar plate by preventing deformations of the polar plate along any bending axis contained in the surface plane P11 H, including along the longitudinal direction X. The groups 64, thanks to the interlocking of their stiffening reliefs 66, 68, 70, are therefore particularly effective in stiffening the edges 50.

[0172] The simultaneous association of the stiffening relief 60 and the groups 64 thus makes it possible to obtain a polar plate 10 whose edges are particularly rigid.

[0173] Furthermore, the fact that the stiffening relief 60 and the groups 64 of stiffening reliefs 66, 68, 70 are formed directly on the polar plate 10, in the hollow example, is particularly advantageous for facilitating the manufacture of the polar plate: the stiffening relief 60 and the groups 64 of stiffening reliefs 66, 68, 70 can advantageously be formed by stamping simultaneously with the walls 40 and the channels 40. In addition, the filling joint 62 is advantageously affixed to the polar plate 10 simultaneously with the peripheral joint 24H and the damping fins 58.

[0174] BIPOLAR SEPARATE

[0175] The invention also relates to a bipolar separator 200 comprising two polar separators as defined above, in practice the first polar separator 5 and the second polar separator 105, which are superimposed along the stacking direction Z. Such a bipolar separator 200 is shown in Figure 8, with only the polar plate 10 of the first polar separator 5 and the polar plate of the second polar separator 105 being shown, the peripheral seal 24H of each polar separator being specifically masked. In Figure 8, the polar plate 10 of the first polar separator 5 is shown in solid lines, while the polar plate of the second polar separator 105 is shown in dashed lines, the second polar separator being superimposed on the first polar separator.

[0176] In particular, when the polar separators 5, 105 include the stiffening ridges 60 described previously, the stiffening ridges 60 of the first polar separator 5 are aligned with the stiffening ridges 60 of the second polar separator 105, along the stacking direction Z. This allows, in particular, the formation of a bipolar separator with a remarkably stiffened edge, thus reducing the risk of deformation, especially during handling. In Figure 8, since the stiffening ridges 60 of the two polar separators 5, 105 are superimposed, they are indistinguishable.

[0177] In particular, when the polar separators 5 and 105 include the stiffening relief groups 64 described previously, these groups are, in the bipolar separator 200, superimposed on each other while filling the spacing locations 74, which further improves the stiffness of the bipolar separator in its boundary zone. In Figure 8, 64 is the group of the first polar separator 5, 64' is the group of the second polar separator 105, 66, 68, and 70 are the stiffening reliefs of group 64, and 66', 68', and 70' are the stiffening reliefs of group 64'. Also marked 74 is the spacing location formed between the groups 64 of the first polar separator 5, and 74' is the spacing location formed between the groups 64' of the second polar separator 105.

[0178] Thus, as can be seen in Figure 8, group 64' partially overlaps two neighboring groups 64 by straddling the spacing location 74 separating said two groups 64, and vice versa with group 64. More precisely, in the example, for each group 64', the stiffening relief 66' partially overlaps the stiffening relief 70 of a first group 64, and the stiffening reliefs 68' and 70' partially overlap the stiffening relief 66 of a second group 64 neighboring the first group 64. Furthermore, the stiffening reliefs 66' and 68' overlap the spacing location 74 formed between said two groups 64. Symmetrically, each group 64 overlaps one of the spacing locations 74'.

[0179] Thanks to the superposition of groups 64 and 64', there is no axis intersecting the bypass zone 56 of the first polar separator 5 or the second polar separator 105, perpendicular to the stacking direction Z, that can cross the bypass zone 56 without intersecting at least one stiffening relief 66, 68, 70 of a group 64 or without intersecting at least one stiffening relief 66', 68', 70' of a group 64'. In other words, at the scale of the bipolar separator, there is no straight space crossing the bypass zone 56 of either of the two polar separators 5, 105 without intersecting at least one group 64, 64'. Therefore, at the scale of the bipolar separator, there is no bend line, i.e., there is no preferred direction of deformation, so the overlap of groups 64, 64' is particularly effective in stiffening the bipolar separator. 200.MISCELLANEOUS

[0180] In the example, the bypass zones 56 are delimited by the longitudinal portions 52 of the peripheral seal 24H, these portions thus forming peripheral sealing elements received on the lateral sealing locations 54. In a non-represented variant of the invention, the lateral sealing locations 54 receive other types of peripheral sealing elements to delimit the bypass zones 56, such as for example a bond between the pole plate 10 and the peripheral zone 97 of the membrane-electrode assembly 90 facing the plate face 11H.

[0181] As schematically shown in Figure 2, face 1110 of separator 105 has a structure and function similar to that of face 11H of separator 5, except that face 1110 guides the secondary reactive fluid and not the primary reactive fluid. Face 1110 and face 92 are supported against each other along the Z direction, being superimposed. On face 1110, the polar separator 105 includes a circulation field 1200, which is superimposed with the exchange zone 93, two conveying fields 1210 and 1220, superimposed with the peripheral zone 97, a seal 1240 and two injection rims 1250 and 1260, respectively delimiting the orifices 1150 and 1160. The orifice 1150 supplies face 1110 with the secondary reactive fluid via the rim 1250.The secondary reactive fluid from rim 1250 is guided to the circulation field 1200 via the conveying field 1210, where it participates in the electrochemical reaction by coming into contact with the exchange zone 93. The secondary reactive fluid and reaction products are then guided from the circulation field 1200 to the rim 1260 via the conveying field 1220. The secondary fluid and reaction products are finally discharged through the orifice 1160 from rim 1260. The seal 1240 is interposed between face 1110 and face 92 along the Z direction, forming a main closed loop surrounding at least the circulation field 1200 and the conveying fields 1210 and 1220, thus preventing the secondary reactive fluid from escaping to the periphery.The 1240 seal also includes secondary closed loops to prevent fluid from escaping from distribution ports that are not already surrounded by the main closed loop.

[0182] Any feature described above for one embodiment or variant is applicable to the other embodiments and variants described above, insofar as technically possible.

Claims

33 DEMANDS 1. Pole plate (10), for a stack (2) of a fuel cell (1), the pole plate (10) extending perpendicularly to a stacking direction (Z), the pole plate (10) defining a longitudinal direction (X) and a transverse direction (Y) distinct and perpendicular to the stacking direction (Z), the pole plate (10) comprising a primary face (11H) oriented in the stacking direction (Z), the pole plate (10) comprising: a feed port (15H), passing through the polar plate (10) from the primary face (11H), an evacuation orifice (16H), passing through the polar plate (10) from the primary face (11H), a circulation field (20H), formed by the primary face (11H) and comprising walls (40), projecting along the stacking direction (Z), extending in the longitudinal direction (X) and delimiting channels (42) to guide a flow of primary reactive fluid from the supply port (15H) to the discharge port (16H), the walls (40) comprising a last wall (41) delimiting the circulation field (20H), an edge (50), formed by the primary face (11H) and extending the primary plate (10) beyond the circulation field (20H) along the transverse direction (Y), the last wall (41) bordering the edge (50) to prevent flow of the primary reactive fluid from the circulation field (20H) to the edge (50), a lateral sealing location (54), formed by the edge (50), the lateral sealing location (54) being configured to receive a longitudinal portion (52) of a peripheral sealing element (24H), the longitudinal portion (52) extending over the entire length (L20H) of the circulation field (20H), measured along the longitudinal direction (X), the peripheral sealing element (24H) being configured to contain the primary reactive fluid on the surface of the primary face (11H), a bypass zone (56),formed by the primary face (11H) on the rim (50) and delimited in the transverse direction (Y) by the last wall (41) and by the lateral sealing location (54), the bypass zone (56) being configured to allow a flow of primary reactive fluid from the supply port (15H) to the discharge port (16H) bypassing the circulation field (20H), and, a stiffening relief (60), o formed by the primary face (11 H) on the rim (50), and 34 extending continuously over at least 75% of the length (L20H) of the traffic area (20H), along the longitudinal direction (X), the polar plate (10) being characterized in that the stiffening relief (50) is formed between the last wall (41) and the lateral sealing location (54), along the transverse direction (Y), the stiffening relief (60) being disposed in the bypass zone (56).

2. Polar plate (10) according to claim 1, wherein a ratio of a smaller width (L56) of the bypass zone (56), measured along the transverse direction (Y), to a larger width (L42B) of the channels (42) of the circulation field (20H), measured along the transverse direction (Y), is greater than 2.5, preferably greater than 4, preferably even greater than 7.

3. Polar plate (10) according to any one of claims 1 or 2, wherein a smallest distance (D60) between the stiffening relief (60) and the last wall (41), measured along the transverse direction (Y), is greater than 2 mm, preferably greater than 5 mm.

4. Polar plate (10) according to any one of claims 1 to 3, wherein a width (L60A) of the stiffening relief (60), measured along the transverse direction (Y), is constant and is preferably between 0.30 mm and 2 mm.

5. Polar plate (10) according to any one of claims 1 to 4, wherein the stiffening relief (60) extends over at least 90% of the length (L20H) of the circulation field (20H), along the longitudinal direction (X).

6. Polar plate (10) according to any one of claims 1 to 5, wherein the stiffening relief (60) is rectilinear and extends parallel to the longitudinal direction (X).

7. Polar plate (10) according to any one of claims 1 to 6, wherein the stiffening relief (60) forms a hollow relative to the primary face (11H).

8. Polar plate (10) according to any one of claims 1 to 7, wherein a height (H60) of the stiffening relief (60), measured from the primary face (11H) parallel to the stacking direction (Z), is less than a height (H40) of the walls (40) and a height (H42A) of the channels (42), measured from the primary face (11H) parallel to the stacking direction (Z).

9. Polar plate (10) according to any one of claims 1 to 8, further comprising groups (64) of auxiliary stiffening reliefs (66, 68, 70), the groups (64) being aligned with each other and spaced along the longitudinal direction (X), each group (64) comprising at least two auxiliary stiffening reliefs (66, 68, 70), formed by the primary face (11 H) on the edge (50), between the last wall (41) and the lateral sealing location (54), along the transverse direction (Y), the auxiliary stiffening reliefs (66, 68, 70) being arranged in the bypass zone (56), and in each group (64), the auxiliary stiffening reliefs (66, 68, 70) are nested along the longitudinal direction (X) and along the transverse direction (Y).

10. Polar plate (10) according to claim 9, wherein the groups (64) of auxiliary stiffening reliefs (66, 68, 70) are located between the stiffening relief (60) and the last wall (41), along the transverse direction (Y).

11. Polar separator (5), comprising the polar plate (10) according to any one of claims 1 to 10 and a peripheral seal (24H) received on the primary face (11H) of the polar plate (10), the peripheral seal (24H) forming the peripheral sealing element (24H), a longitudinal portion (52) of the peripheral seal (24H) being received in the lateral sealing location (54).

12. Polar separator (5) according to claim 11, further comprising at least one slowing fin (58), made of material with the peripheral joint (24H), said at least one slowing fin (58) extending from the peripheral joint (24H) towards the circulation field (20H) by crossing the stiffening relief (60).

13. Polar separator (5) according to any one of claims 11 to 12, further comprising a filling joint (62) filling the stiffening relief (60), made of material with the peripheral joint (24H), in which, preferably, the filling joint (62) is flush with the primary face (11H), parallel to the stacking direction (Z).

14. Bipolar separator (200) comprising: a first polar plate (10) according to any one of claims 1 to 10, a first peripheral seal (24H) received on the primary face (11H) of the first polar plate (10), a longitudinal portion (52) of the first peripheral seal (24H) being received in the lateral sealing location (54) of the first polar plate (10), the first peripheral seal (24H) forming the peripheral sealing element associated with the first polar plate (10), a second polar plate according to any one of claims 1 to 10, a second peripheral seal (1240) received on the primary face of the second polar plate, a longitudinal portion of the second peripheral seal being received in the lateral sealing location of the second polar plate, the second peripheral seal forming the peripheral sealing element associated with the second polar plate, in which the first polar plate (10) and the second polar plate are superimposed along the stacking direction (Z), and in which the stiffening relief (60) of the first polar plate (10) is opposite the stiffening relief (60) of the second polar plate, according to the stacking direction (Z).

15. Stack (2) comprising the polar separator (5) according to any one of claims 11 to 13, and a membrane-electrode assembly (90), which extends perpendicularly to the stacking direction (Z), which is superimposed on the polar separator (5), such that the membrane-electrode assembly (90) is arranged in the stacking direction (Z) relative to the polar separator (5), the membrane-electrode assembly (90) comprising: an exchange zone (93), comprising a proton exchange polymer membrane, a peripheral zone (97), surrounding the exchange zone (93) by extending the exchange zone (93) along the transverse direction (Z), and a primary gas diffusion layer, covering the proton exchange polymer membrane, in which the circulation field (20H) is aligned, along the stacking direction (Z), with the exchange zone (93) and with the primary gas diffusion layer, the primary gas diffusion layer being interposed between the circulation field (20H) and the exchange zone (93) along the stacking direction (Z), and in which the rim (50) is aligned with the peripheral zone (97), along the stacking direction (Z).

16. Fuel cell (1) comprising the stack (2) according to claim 15 or the bipolar separator (200) according to claim 14.

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