Cell for a fuel cell and fuel cell comprising such a cell

Abstract

The present invention relates to a cell (2) for a fuel cell (1), the cell (2) comprising a first plate (100) including a peripheral region (102), a membrane electrode assembly (200) superimposed on the first plate and including a peripheral portion (202) and at least one gas diffusion layer (205) interposed between a polymeric proton exchange membrane (204) and the first plate, and a first peripheral seal (300) for sealing reactant fluids. and a first peripheral seal (300) for providing a seal between a bypass region (50) of the cell on the one hand and an exterior region (3) of the cell on the other hand, the seal comprising a main portion (301) and at least one fin (302) extending into the bypass region, characterized in that the fin further comprises an end portion (306) spaced between the gas diffusion layer and the peripheral region and an intermediate portion (305) oblique to the main portion.

Description

[Technical Field]

[0001] The present invention relates to a cell for a fuel cell and to a fuel cell comprising such a cell. [Background technology]

[0002] Patent Document 1 describes a fuel cell and at least one seal member for such a cell. The cell includes a membrane electrode assembly including a gas diffusion layer and two separator plates disposed on either side of the membrane electrode assembly, each plate including a flow region with a gas flow channel. Each seal member extends from the inner surface of the annular seal between the separator plate and the electrolyte membrane and contacts the surface of the membrane electrode assembly, particularly the gas diffusion layer, thereby restricting the inflow of gas into the bypass region. This region is commonly referred to as the "bypass region." It may be desirable to restrict the flow of gas through the bypass region because gas could bypass the flow region without reacting, reducing the efficiency of the cell.

[0003] In this known cell, a seal is interposed between the peripheral region of the separator plate and the membrane electrode assembly. The peripheral region is flush with the flow region, while the gas flow channels are grooves recessed in the separator plate. However, it may be more advantageous to use a press-formed sheet metal separator plate, in which case the bypass region may partially extend below the gas diffusion layer. In this case, the seal of the known cell may not be sufficiently effective in blocking gas flow in the bypass region. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 8,003,273 Summary of the Invention

[0005] SUMMARY OF THE INVENTION An object of the present invention is to overcome the above drawbacks by providing a peripheral seal that more effectively blocks gas flow.

[0006] To this end, the present invention provides a peripheral seal for a cell for a fuel cell, the peripheral seal comprising: A main portion, the main portion being arranged along the stacking direction of the fuel cell, a peripheral region belonging to a plate of the cell, the plate extending parallel to a main plane of the cell, the main plane being perpendicular to the stacking direction, the plate containing a flow field for the reactant fluids surrounded by the peripheral region; a main portion configured to be interposed between a peripheral portion belonging to a membrane electrode assembly, the membrane electrode assembly further including at least one gas diffusion layer; at least one fin, the fin including a connecting portion, the fin being attached to the main portion via the connecting portion; The present invention relates to a peripheral seal comprising:

[0007] According to the invention, at least one of the fins further comprises: an end portion terminating the fin, the end portion being configured to be interposed between the gas diffusion layer and the peripheral region in the stacking direction; an intermediate portion connecting the connecting portion to the end portion, the intermediate portion being configured to be oblique to the main portion of the peripheral seal when projected onto the main plane; Equipped with.

[0008] The idea behind the present invention is to block the flow of reactant fluid between the gas diffusion layer and the peripheral region of the electrode plate by interposing fins, in this case the ends of the fins, between the gas diffusion layer and the peripheral region of the electrode plate. In this way, even when the reactant fluid partially flows under the gas diffusion layer, the fins can block the flow, increasing the proportion of reactant fluid in the flow field and thus improving the cell efficiency. Furthermore, because the middle portion of the fin is oblique to the main portion, the risk of lateral deformation of the main portion of the first peripheral seal under the tensile force exerted by the fin is reduced, despite the fact that the ends of the fin are interposed between the gas diffusion layer and the peripheral region of the electrode plate and may be compressed. In particular, the primary tensile force caused by the compression of the ends by the gas diffusion layer is converted into a torsional and / or bending force in the middle portion, which deforms the middle portion. Therefore, the resultant force acting on the main portion is significantly smaller than the primary tensile force, and is insufficient to deform the main portion or only slightly deforms it. The first perimeter seal is then sealed from the exterior of the stack, allowing the cell to operate properly.

[0009] The peripheral seal may comprise the following features, individually or in any technically possible combination: The peripheral seal comprises a plurality of fins, each of which is connected to the main part only via a connecting part. The connecting portion is configured to extend perpendicular to the main portion in projection onto the main plane. The end portion is configured to extend perpendicular to the main portion in projection onto the main plane. At least some of the end portions, intermediate portions and connecting portions are configured to be straight in projection onto the main plane. a portion of the fin is configured to be curved in projection onto the main plane; The connection has openings that allow fluid to flow through the fins. The main part of the peripheral seal and the fins are formed in one piece. The peripheral seal further comprises a dam portion, the dam portion being parallel to the main portion, the dam portion connecting the ends of the plurality of fins, the dam portion being formed in one piece together with the first peripheral seal, and the dam portion being configured to be interposed between the gas diffusion layer and the electrode plate along the stacking direction.

[0010] The present invention also provides a cell for a fuel cell, the cell comprising a plate and a peripheral seal, the plate comprising: a peripheral region; a flow field for a reactant fluid surrounded by the peripheral region.

[0011] The cell may comprise the following characteristics, individually or in any technically possible combination: The cell further comprises: a membrane electrode assembly, the membrane electrode assembly extending parallel to the main plane of the cell and superposed on the first electrode plate in the stacking direction; a peripheral portion facing the peripheral region in the stacking direction; a central portion including a polymeric proton exchange membrane flanked by peripheral portions; and a membrane electrode assembly including at least one gas diffusion layer interposed between a polymer proton exchange membrane and an electrode plate in a stacking direction; The peripheral seal provides a seal against reactant fluids between, on the one hand, a bypass region of the cell defined inside the cell between the peripheral portion of the membrane electrode assembly and the peripheral region, and, on the other hand, an exterior region of the cell located beyond the main portion and opposite the bypass region, and at least one fin extends into the bypass region. The contacting portions of the ends are compressed between the gas diffusion layer and the peripheral area. the flow field defines a plurality of channels for flow of reactant fluids, the channels extending in a longitudinal direction perpendicular to the stacking direction, each channel comprising: a channel bottom that belongs to the flow field and extends parallel to the longitudinal direction; and two channel teeth belonging to the flow field and extending parallel to the longitudinal direction, the channel teeth being arranged on either side of the channel bottom and protruding from the channel bottom, each channel tooth being in contact with a gas diffusion layer in the stacking direction. The channel teeth further protrude from the peripheral region in the stacking direction.

[0012] The invention also relates to a fuel cell comprising cells, at least one of which is as described above, the cells being stacked along a stacking direction to form a stack.

[0013] The present invention also aims to overcome the drawbacks of the prior art by providing a new fuel cell that has a bypass region that extends below the gas diffusion layer, without compromising the seal of the cell from the outside, thereby improving efficiency.

[0014] To this end, the present invention also relates to a cell for a fuel cell, the cell comprising a first electrode plate extending parallel to a main plane of the cell, the main plane being perpendicular to a stacking direction of the fuel cell, the first electrode plate having a peripheral region and a flow field for reactant fluids surrounded by the peripheral region, and a membrane electrode assembly extending parallel to the main plane of the cell and superposed on the first electrode plate in the stacking direction, the membrane electrode assembly comprising a peripheral portion facing the peripheral region in the stacking direction, a central portion including a polymer proton exchange membrane and flanked by the peripheral portion, and at least one gas diffusion layer interposed between the polymer proton exchange membrane and the first electrode plate in the stacking direction. The cell further comprises a first peripheral seal, the first peripheral seal having a main portion interposed between the peripheral region and a peripheral portion of the membrane electrode assembly in the stacking direction, the first peripheral seal providing a seal for reactant fluids between a bypass region of the cell defined inside the cell between the peripheral portion of the membrane electrode assembly and the peripheral region, on the one hand, and an external region of the cell located across the main portion and opposite the bypass region, and at least one fin extending into the bypass region and including a connecting portion, the fin being attached to the main portion via the connecting portion. The fin further comprises end portions interposed between the gas diffusion layer and the peripheral region in the stacking direction, and intermediate portions connecting the connecting portion to the end portions, the intermediate portions being oblique to the main portion of the first peripheral seal in projection onto the main plane.

[0015] One idea behind this cell is to interpose fins between the gas diffusion layer and the peripheral region of the electrode plate to block the flow of reactant fluid between the gas diffusion layer and the peripheral region of the electrode plate. In this way, even when the bypass region partially extends below the gas diffusion layer, the fins can block the flow of reactant fluid, allowing a higher proportion of reactant fluid in the flow field and thus improving cell efficiency. Furthermore, because the middle portion of the fin is oblique to the main portion, the risk of lateral deformation of the main portion of the first peripheral seal under the tensile force exerted by the fin is reduced, despite the fact that the ends of the fin are interposed between the gas diffusion layer and the peripheral region of the electrode plate and may be compressed. In particular, the primary tensile force caused by compression of the ends by the gas diffusion layer is converted into a twisting and / or bending force at the oblique portion, which deforms the oblique portion. Therefore, the main portion is subjected to a resultant force significantly smaller than the primary tensile force, which is insufficient to deform the main portion or only slightly deforms the main portion. The first perimeter seal is then sealed from the exterior of the stack, allowing the cell to operate properly.

[0016] The cells of the present disclosure may comprise the following characteristics, taken individually or in any technically feasible combination: the connecting portion extends, in projection onto the main plane, perpendicular to the main portion of the first peripheral seal; the end portion extends perpendicular to the main portion of the first peripheral seal in projection onto the main plane; At least one of the end portion, the intermediate portion and the connecting portion is linear when projected onto the main plane. A portion of the fin is curved in projection onto the main plane. The contacting portions of the ends are compressed between the gas diffusion layer and the peripheral area. The connection has openings that allow fluid to flow through the fins. The cell further comprises a dam portion, the dam portion being parallel to the main portion, the dam portion connecting the ends of the plurality of fins, and the dam portion being interposed between the gas diffusion layer and the first electrode plate in the stacking direction, the dam portion being formed in one piece together with the first peripheral seal. The main part and the fins of the first peripheral seal are formed in one piece. the flow field defines a plurality of channels for the flow of reactant fluids, the channels extending along a longitudinal direction perpendicular to the stacking direction, each channel being defined by a channel bottom belonging to the flow field and extending parallel to the longitudinal direction, and two channel teeth belonging to the flow field and extending parallel to the longitudinal direction, the channel teeth being arranged on either side of the channel bottom and protruding relative to the channel bottom, each channel tooth being in contact with a gas diffusion layer in the stacking direction. The channel teeth further protrude from the peripheral region in the stacking direction. The membrane electrode assembly comprises a holding frame which forms a peripheral portion and is located laterally of the central portion. The cell further comprises a second electrode plate positioned relative to the first electrode plate beyond the membrane electrode assembly in the stacking direction, and a second peripheral seal interposed between the second electrode plate and the membrane electrode assembly in the stacking direction.

[0017] The present disclosure also relates to a fuel cell comprising cells, at least one of which is as described above, stacked along a stacking direction to form a stack.

[0018] The invention will be better understood from reading the following description, given by way of example only, with reference to the drawings in which: [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is an exploded view of a portion of a fuel cell according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of a portion of a fuel cell stack including the cell of FIG. [Figure 3] FIG. 3 is another cross-sectional view of a portion of the cell of FIG. [Figure 4] FIG. 4 is a top view of a portion of the cell of the previous figure, showing cross section II-II' of FIG. 2 and cross section III-III' of FIG. [Figure 5] FIG. 5 is a cross-sectional view similar to FIG. 2, with the stack shown in an exploded state. [Figure 6] FIG. 6 is a cross-sectional view of a part of a stack including a cell according to a second embodiment of the present invention. [Figure 7] FIG. 7 is a top view of a portion of the cell of FIG. 6, showing cross section IV-IV' of FIG. [Figure 8] FIG. 8 is a top view of a portion of a cell according to a third embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view of a part of a stack including a cell according to a fourth embodiment of the present invention. [Figure 10] FIG. 10 is a top view of a portion of the cell of FIG. 9, showing cross section VV' of FIG. [Figure 11] FIG. 11 is a top view of the fifth embodiment of the present invention. [Figure 12] FIG. 12 is a cross-sectional view of a part of a stack including a cell according to a sixth embodiment of the present invention. [Figure 13] FIG. 13 is a top view of a portion of the cell of FIG. 12, showing cross section VI-VI' of FIG. [Figure 14] FIG. 14 is a cross-sectional view of a part of a stack including a cell according to a seventh embodiment of the present invention. [Figure 15] FIG. 15 is a cross-sectional view of a part of a cell according to an eighth embodiment of the present invention. [Figure 16] FIG. 16 is a cross-sectional view of a part of a cell according to a ninth embodiment of the present invention. [Figure 17] FIG. 17 is a top view of the ninth embodiment, showing the cross section VIII-VIII' of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0020] 1 to 5 show a first embodiment of the present invention.

[0021] 1 shows a first or cathode plate 100 and a membrane electrode assembly 200 that form part of a cell 2 of a fuel cell 1. The cell 2 also includes a second or anode plate 100' shown in FIG.

[0022] As shown in Figure 2, the cathode plate 100 is perpendicular to the stacking direction X of the fuel cell 1, which points upward. The cathode plate 100 extends parallel to the main plane P of the cell 2, which is perpendicular to the stacking direction X. Also defined are a longitudinal direction Y extending forward in Figure 2 and a lateral direction Z extending from left to right in Figure 2, which extend within the main plane P and are perpendicular to each other and to the stacking direction X.

[0023] The cathode plate 100 may be made of a conductive material, for example, a metal such as stainless steel or graphite. The cathode plate 100 has a peripheral region 102, an opening 101, two homogenization fields 104, and a flow field 103.

[0024] The peripheral region 102 extends around the entire periphery of the cathode plate 100 and surrounds the opening 101, the homogenization field 104, and the flow field 103. The opening 101, the homogenization field 104, and the flow field 103 are disposed inside the peripheral region 102. The peripheral region 102 extends in a plane perpendicular to the stacking direction X and parallel to the main plane P.

[0025] The flow field 103 extends between the two homogenization fields 104 along the longitudinal direction Y. On one surface of the cathode plate 100 facing the membrane electrode assembly 200, i.e., the side along the stacking direction X, the flow field 103 includes flow channels 105 formed in a recess and extending substantially parallel to the longitudinal direction Y. The flow channels 105 may be defined by grooves cut into the cathode plate 100 or may be defined by press-forming the cathode plate 100.

[0026] Each flow channel 105 is defined in its depth direction along the stacking direction X by a flow channel bottom 1051 formed by the cathode plate 100 and extending along the longitudinal direction Y. The flow channel bottom 1051 may be substantially flat, as shown in the simplified illustration, but more typically has a slightly rounded profile in cross section along the transverse direction Z. In certain embodiments, such as those shown in FIGS. 2 and 3 , the flow channel bottom 1051 is flush with the peripheral region 102 at least at the location where the flow channel depth along the stacking direction X is greatest. Alternatively, the flow channel bottom 1051 is recessed from the peripheral region 102 in the stacking direction X.

[0027] Each flow channel 105 is further defined by two channel teeth 1052 formed by the cathode plate 100 and projecting from the channel bottom 1051 in the stacking direction X. Preferably, the channel teeth 1052 also project from the peripheral region 102 in the stacking direction X. The channel teeth 1052 are substantially flat and parallel to the channel bottom 1051. Alternatively, the channel teeth 1052 have a slightly rounded profile in a plane passing through a cross section including the transverse direction Z and the stacking direction X. The channel teeth 1052 surround the channel bottom 1051 along its length in the longitudinal direction Y.

[0028] The channel bottom 1051 is continuously connected to each channel tooth 1052 by an inclined portion 1053 formed by the cathode electrode plate 100. Therefore, the channel 105 is also defined by the two inclined portions 1053.

[0029] Each opening 101 is intended for each cell 2 of the fuel cell 1 either for the introduction of a reactant fluid or a cooling fluid or for the discharge of a reactant fluid or a cooling fluid. These openings 101 have a closed contour. Three openings 101 are arranged on one side of the cathode plate 100 in the longitudinal direction Y and aligned along the transverse direction Z. Three other openings 101 are arranged on the other side of the cathode plate 100 in the longitudinal direction Y and are also aligned along the transverse direction Z. For each reactant fluid or cooling fluid, i.e. for each fluid flow field of the cell, one opening 101 forms a fluid supply to that flow field, and the other opening 101, located on the opposite side of the cathode plate 100 in the longitudinal direction Y, serves for the discharge of fluid from that flow field.

[0030] Each homogenization field 104 is disposed between the flow field 103 and the openings 101 in the longitudinal direction Y. On the side of the cathode plate 100 facing the membrane electrode assembly 200, i.e., in the stacking direction X, each homogenization field 104 may include channels arranged, for example, in a fan-like orientation. These channels connect one of the openings 101 to the flow field 103. The channels of the homogenization field 104 may be similar to the channels of the flow field 103, except for their orientation, and may be formed in a similar manner, as illustrated. However, the channels of the homogenization field 104 may differ from the channels of the flow field 103, for example, in width and / or depth. Similarly, the channels of the homogenization field 104 may be manufactured in a different manner than the channels of the flow field 103, in particular using a different technological process. For example, the flow channels of the homogenization field 104 may be fabricated in the form of ribs added by adding a metal, elastomer, or polymer material to a portion of the cathode plate 100, which may or may not be flat, while the flow channels 105 of the flow field 103 may be made by press molding, or vice versa.

[0031] For the cathode plate 100, the first homogenization field 104 distributes the reactant fluid coming from one of the openings 101b in the longitudinal direction Y so that it flows throughout the flow field 103. The second homogenization field 104 enables the reactant fluid distributed throughout the flow field 103 to be discharged to the other opening 101b located on the opposite side of the cathode plate 100 in the longitudinal direction Y, where the reactant fluid is discharged. Therefore, on the side facing the membrane electrode assembly 200, only one of the reactant fluids flows in the longitudinal direction Y through the flow field 103 from one of the openings 101 to the other opening 101 on the opposite side. For the cathode plate 100, the reactant fluid in question is a cathode reactant fluid, such as air or oxygen. On this side of the cathode plate 100, only opening 101b supplies and discharges fluid, while the contours of openings 101a and 101c are intended to be sealed, thereby preventing fluid passing through openings 101a and 101c from coming into contact with the cathode reactant fluid on this side of the cathode plate 100.

[0032] The membrane electrode assembly (MEA) 200 faces the cathode plate 100 in the stacking direction X, and is parallel to the main plane P. The MEA 200 includes a peripheral portion 202, an opening 201, and a central portion 203.

[0033] The peripheral portion 202 extends around the entire periphery of the MEA 200 and surrounds the opening 201 and the central portion 203 located inside the peripheral portion 202. The opening 201 has a closed contour. The peripheral portion 202 extends in a plane perpendicular to the stacking direction X and parallel to the main plane P.

[0034] The openings 201 are formed in the membrane electrode assembly (MEA) 200 to allow reactant fluids to pass through the MEA in the stacking direction X. Each opening 201 is arranged to extend one of the openings 101 of the cathode plate 100 in the stacking direction X. In other words, the openings 101 and the openings 201 face each other in the stacking direction X. In this example, each opening 201 has the same shape as the opening 101 opposite it.

[0035] The central portion 203 of the MEA 200 faces the flow field 103 and completely covers the flow field 103 in the stacking direction X. The peripheral edge of the central portion 203 may overlap the inner edge of the peripheral portion 202.

[0036] The central portion 203 of the MEA 200 includes a membrane 204, which is a polymeric proton exchange membrane. The membrane 204 extends parallel to a major plane P, faces the flow field 103 in a stacking direction X, and is substantially flat. Preferably, the membrane 204 is coplanar with the peripheral portions 202. The membrane 204 may be coated with a catalyst layer on one or both of its faces parallel to the major plane P. As shown in FIG. 2, the membrane 204 may extend beyond the flow field 103, particularly if the central portion 203 overlaps a portion of the peripheral portions 202.

[0037] The MEA 200 advantageously comprises a holding frame 206 for supporting the membrane 204. The holding frame 206 then forms the peripheral portion 202. The holding frame 206 preferably consists of two identically shaped half frames intended to abut flat against each other and made, for example, from a polymer film, such as 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, glued together. As shown in FIGS. 2, 3, and 5, to hold the membrane 204, the holding frame 206 can clamp, in particular, the outer edge of the membrane 204 in the stacking direction X. In this case, the holding frame 206 grips the entire portion of the membrane 204 that overlaps the peripheral portion 202 in the stacking direction X. The holding frame 206 therefore has a central opening, the contour of which, if appropriate, defines the central portion 203 of the MEA 200. The central opening allows access to membrane 204 for reactant fluids flowing through the flow field.

[0038] Alternatively, rather than a retaining frame 206, a single membrane, for example membrane 204, may form both central portion 203 and peripheral portion 202.

[0039] The gas diffusion layer 205 extends parallel to the main plane P. The gas diffusion layer 205 is interposed between the central portion 203 and the cathode plate 100 in the stacking direction X. In particular, the gas diffusion layer 205 completely covers the central portion 203, i.e., the membrane 204, and advantageously overhangs the peripheral portion 202, i.e., the inner peripheral edge of the holding frame 206 that holds the membrane 204. In particular, the gas diffusion layer 205 rests on the channel teeth 1052 of the channels 105 in the stacking direction X and abuts the membrane 204 in the opposite direction. The gas diffusion layer 205 is advantageously formed from a porous material that allows diffusion of the cathode reactant fluid from the channels 105 to the membrane 204 during operation of the cell 2, and in some cases, allows diffusion of reaction products from the membrane 204 to the channels 105 for removal.

[0040] The cell 2 includes a first peripheral seal 300, which is interposed between the cathode plate 100 and the MEA 200 along the stacking direction X. The peripheral seal 300 includes a main portion 301 and fins 302.

[0041] 1, for example, by overmolding onto the cathode plate 100, or alternatively, may be formed onto the MEA 200, or may be formed separately from the cathode plate 100 and the MEA 200 and then assembled to either by any means known to those skilled in the art. The first perimeter seal 300 is ideally made from an elastomeric material, for example, silicone or ethylene propylene diene monomer (EPDM), and is impermeable to the cathode fluid used in the fuel cell 1.

[0042] The first peripheral seal 300 comprises a main portion 301 and at least one, preferably a plurality of, fins 302. Preferably, each of the plurality of fins 302 is discrete, i.e., not connected to, for example, other fins 302, but connected only to the main portion 301. In particular, the blades 302 are spaced apart from one another.

[0043] The main portion 301 forms a closed loop, which in this example extends along the peripheral region 102 over the entire periphery of the cathode plate 100. Correspondingly, the main portion 301 extends in a closed loop along the peripheral portion 202 of the MEA 200, here in a closed loop along the retaining frame 206, over the entire periphery of the peripheral portion 202. The main portion 301 is interposed between the peripheral region 102 and the peripheral portion 202 in the stacking direction X and seals, over the entire periphery, the space defined between the region 102 and the portion 202 in the stacking direction X. In particular, the main portion 301 surrounds the flow field 103, the homogenization field 104, if present, and the opening 101b serving this side of the cathode plate 100, or possibly all the openings 101 of the cathode plate 100. The main portion 301 also surrounds the gas diffusion layer 205 and the surface of the membrane 204 facing away from the stacking direction X and towards the cathode plate 100. The main portion 301 includes two opposing inner longitudinal surfaces 303, which are disposed laterally on either side of the flow field 103. Each inner longitudinal surface 303 extends along a portion of the main portion 301 parallel to the longitudinal direction Y and faces the flow field 103. Each inner longitudinal surface 303 connects the peripheral region 102 to the peripheral portion 202 in the stacking direction X.

[0044] The main portion 301 of the first perimeter seal 300, the cathode plate 100, and the MEA 200 define therebetween the cathode compartment 40. The main portion 301 seals the cathode compartment 40 from the exterior of the cell 2, and in particular from an exterior region 3 located beyond the main portion 301 of the first perimeter seal 300 relative to the cathode compartment 40.

[0045] Two bypass regions 50 are defined in the cathode compartment 40. Each bypass region 50 is defined between the cathode plate 100 and the MEA 200 in the stacking direction X, and between the flow field 103 and the gas diffusion layer 205 on the one hand and the main portion 301 of the first peripheral seal 300 for a portion of the main portion 301 extending in the longitudinal direction Y on the other hand. Each bypass region 50 extends along the flow field 103 in the longitudinal direction Y and also extends from one homogenization field 104 to the other homogenization field 104. The flow field 103 is disposed between the two bypass regions 50 in the transverse direction Z.

[0046] The purpose of the fins 302 is to reduce or prevent the flow of cathode reactant fluid in the longitudinal direction Y in the bypass region 50, particularly to concentrate the fluid toward the flow field 103. To do this, each fin 302 occludes the cross-section of the bypass region 50 that it occupies, taken perpendicular to the longitudinal direction Y. The fins 302 are disposed along the main portion 301 of the first peripheral seal 300 on one side or the other of the cathode bypass region 50, or on both sides. Each fin 302 is attached to one of the inner longitudinal surfaces 303 of the main portion 301. Each fin 302 extends from the inner longitudinal surface 303 generally along the transverse direction Z toward the interior of the main portion 301, i.e., toward the flow field 103. The fins 302 may be formed in one piece with the main portion 301.

[0047] Each fin 302 includes, in order from the main portion 301 , a connecting portion 304 , an intermediate portion 305 , and an end portion 306 .

[0048] In the example shown, each fin 302 advantageously has a wall-like shape with an extension in the main plane P, the extension having a broken line profile, a curved line profile or a profile consisting of a combination of one or more straight lines and / or one or more broken lines and / or one or more curves.

[0049] Optionally, each wall-like fin 302, preferably at any point considered within its extension, has, in a cross section through a plane perpendicular to the extension of the wall at this point considered, a thickness in the longitudinal direction Y, also called width, and a thickness in the stacking direction X, the thickness in the longitudinal direction Y being smaller than the thickness in the stacking direction X, in particular over at least part of the length of the fin 302 in the transverse direction Z, or even over the entire length, extending from the cathode plate 100 to the MEA 200. Alternatively, the thickness in the longitudinal direction Y may be greater than the thickness in the stacking direction X, or may vary depending on the point on the extension.

[0050] Preferably, connecting portion 304, intermediate portion 305, and end portion 306 each have the same width, i.e., the same thickness measured in the Y direction. In other words, each fin 302 has a substantially constant thickness in the Y direction. This minimizes the amount of material used to form fins 302, ensures accurate formation of fins 302, and ensures material continuity, particularly during the manufacturing process of peripheral seal 300.

[0051] The fins 302 are connected to the main part 301 via connecting portions 304 extending from the longitudinal inner surface 303. In particular, the fins 302 are attached to the main part 301 only via the connecting portions 304.

[0052] In the present example, the connecting portion 304 is linear, and its projection onto the main plane P is perpendicular to the longitudinal direction Y, i.e., parallel to the transverse direction Z. The connecting portion 304 is interposed along the stacking direction X between the peripheral region 102 of the cathode plate 100 and the peripheral portion 202 of the MEA 200.

[0053] The intermediate portion 305 of the fin 302 is attached to the connecting portion 304 and extends it in the direction of the flow field 103. In this example, the intermediate portion 305 is straight, and its projection onto the main plane P is oblique to the main portion 301 or oblique to the longitudinal direction Y. The intermediate portion 305 is interposed along the stacking direction X between the peripheral region 102 of the cathode plate 100 and the peripheral portion 202 of the MEA 200.

[0054] The length of the connecting portion 304 when projected onto the main plane P is preferably shorter than the length of the intermediate portion 305 of the fin 302, for example less than 50% of the length of the intermediate portion 305, preferably less than 30%, and even more advantageously less than 10%.

[0055] The end portions 306 of the fins 302 are attached to the intermediate portion 305 and extend it towards the flow field 103. The end portions 306 terminate the fins 302. In this example, the end portions 306 are straight and their projection onto the main plane P is perpendicular to the longitudinal direction Y, i.e. parallel to the transverse direction Z.

[0056] The intermediate portion 305 and the end portion 306 are not attached to the main portion 301 other than by the connecting portion 304. At least a portion of the fin 302, namely the contact portion 307 of the fin 302 belonging to the end portion 306 and including the end of the fin 302, is interposed between the gas diffusion layer 205 and the peripheral region 102 in the stacking direction X. Optionally, another portion of the end portion 306, by which the end portion 306 is attached to the intermediate portion 305, is interposed between the peripheral region 102 and the peripheral portion 202.

[0057] The end portion 306 and the intermediate portion 305 form an angle therebetween that is advantageously between 110 and 150 degrees, ideally 120 degrees. The intermediate portion 305 and the connecting portion 304 form an angle therebetween that is advantageously between 110 and 150 degrees, ideally 120 degrees.

[0058] Thus, according to the embodiment shown in FIGS. 1 to 5, each fin 302 has, in projection onto the main plane P, an extension path that forms a zigzag from the main portion 301 towards the flow field 103.

[0059] As shown in FIGS. 2, 3, and 4, the contact portion 307 of the fin 302 is elastically deformed by compression along the stacking direction X between the gas diffusion layer 205 and the peripheral region 102. When the contact portion 307 is compressed in this manner, its thickness measured along the stacking direction X is smaller than the thickness of the other portions of the fin 302, particularly the connecting portion 304 and the middle portion 305. In the undeformed state of the fin 302 shown in FIG. 5, the contact portion 307 can be expected to initially have the same thickness along the stacking direction X as the other portions of the fin 302. This compressive deformation of the contact portion 307 can also deform the middle portion 305. As shown in the cross section of FIG. 3, the middle portion 305 can absorb this deformation of the end portion 306 by twisting slightly. The fact that the middle portion 305 is oblique to the longitudinal direction Y advantageously prevents this deformation from being transmitted to the connecting portion 304 and the main portion 301. Thus, the particular orientation of the intermediate portion 305 prevents the main portion 301 from being subjected to mechanical stresses associated with the flattening of the contact portion 307 between the layer 205 and the peripheral region 102 .

[0060] The anode plate 100' is similar to the cathode plate 100 except for a few differences, most of which are described below. The anode plate 100' extends parallel to the main plane P of the cell 2, is perpendicular to the stacking direction X, and is positioned across the MEA 200 to face the cathode plate 100.

[0061] Anode plate 100' is advantageously formed from the same material as cathode plate 100 and, like cathode plate 100, comprises peripheral region 102' similar to peripheral region 102, an opening similar to opening 101, two homogenization fields similar to field 104, and flow field 103' similar to flow field 103.

[0062] The peripheral region 102' extends around the entire periphery of the anode plate 100' and surrounds the openings, homogenization field, and flow field 103'. As with the cathode plate 100, the openings, homogenization field, and flow field 103' of the anode plate 100' are located inside the peripheral region 102'. The peripheral region 102' extends in a plane perpendicular to the stacking direction X and parallel to the main plane P.

[0063] Similar to the openings 101, each opening of the anode plate 100′ is used for introducing or discharging a reactant fluid or a cooling fluid and cooperates with the openings 101. In the stacking direction X, each opening of the anode plate 100′ is connected to one of the openings 101 via one of the openings 201 of the MEA 200.

[0064] The flow field 103' extends between the two homogenization fields of the electrode plate 100' in the longitudinal direction Y. On the surface of the anode electrode plate 100' facing the membrane electrode assembly 200, i.e., in the direction opposite to the stacking direction X, the flow field 103' includes channels 105' that are recessed and extend substantially parallel to the longitudinal direction Y. The channels 105' may be defined by grooves cut into the anode plate 100' or by press-molding the anode plate 100'.

[0065] Each channel 105′ is defined in its depth direction in the stacking direction X by a channel bottom 1051′ formed by the anode plate 100′ and extending along the longitudinal direction Y. The channel bottom 1051′ may be substantially flat, as shown in simplified form in the figure, but more typically has a slightly rounded profile in cross section through a transverse plane including the transverse direction Z. In certain embodiments, such as that shown in FIG. 2 , the channel bottom 1051′ is flush with the peripheral region 102′, at least at the location where the depth of the channel 105′ along the stacking direction X is greatest. Although not shown, the channel bottom 1051′ alternatively protrudes from the peripheral region 102′ in the stacking direction X.

[0066] Each flow channel 105′ is further defined by two channel teeth 1052′ formed by the anode plate 100′ and recessed from the channel bottom 1051′ in the stacking direction X. Preferably, the channel teeth 1052′ are also recessed from the peripheral region 102′ in the stacking direction X. The channel teeth 1052′ are substantially flat and parallel to the channel bottom 1051′. Alternatively, the channel teeth 1052′ have a slightly rounded profile in a plane passing through a cross section including the transverse direction Z and the stacking direction X. The channel teeth 1052′ surround the channel bottom 1051′ along its length in the longitudinal direction Y.

[0067] The channel bottom 1051' is continuously connected to each channel tooth 1052' by an inclined portion 1053' formed by the anode plate 100'. Thus, the channel 105' is also defined by two inclined portions 1053'.

[0068] Similar to the cathode plate 100, each homogenization field of the anode plate 100' is disposed between the flow field 103' and the opening of the anode plate 100' in the longitudinal direction Y and may include, for example, a fan-shaped flow path. The first homogenization field distributes the reactant fluid coming from one of the openings of the anode plate 100' so that it flows within the flow field 103', and the second homogenization field allows the reactant fluid distributed throughout the flow field 103' to be discharged to the other opening. The flow field 103 of the cathode plate 100 is supplied with a cathode reactant fluid such as air or oxygen through opening 101b, while the flow field 103' is supplied with an anode reactant fluid such as hydrogen through an opening of the anode plate 100' corresponding to opening 101a. The contours of other openings in anode plate 100' corresponding to openings 101b and 101c are sealed, thereby allowing only the anode reactant fluid to flow within flow field 103'.

[0069] The MEA 200 includes another gas diffusion layer 205', which extends parallel to the main plane P. The gas diffusion layer 205' is interposed between a central portion 203 of the MEA 200 and the anode plate 100' in the stacking direction X. The central portion 203 of the MEA 200 is therefore interposed between the two gas diffusion layers 205 and 205' in the stacking direction X. In particular, the gas diffusion layer 205' completely covers the central portion 203 of the MEA 200, i.e., the membrane 204, and advantageously overhangs the peripheral portion 202, i.e., the inner peripheral edge of the holding frame 206 that holds the membrane 204. In particular, the gas diffusion layer 205' rests on the channel teeth 1052' of the channels 105' in the opposite direction to the stacking direction X. Gas diffusion layer 205' is advantageously formed from a porous material to allow the anode reactant fluid to diffuse from flow channels 105' to membrane 204 when cell 2 is operating, and optionally, reaction products to diffuse from membrane 204 to flow channels 105' for removal.

[0070] The supply of anode reactant fluid and cathode reactant fluid through gas diffusion layers 205 and 205' via flow fields 103 and 103' causes a chemical reaction between the reactant fluids at membrane 204 of cell 2. The exchange of protons between the anode reactant fluid and the cathode reactant fluid across the membrane generates a potential difference between cathode plate 100 and anode plate 100'.

[0071] Cell 2 includes a second peripheral seal 300′, preferably similar to first peripheral seal 300, interposed between anode plate 100′ and MEA 200 along stacking direction X. Peripheral seal 300′ includes a main portion 301′ and fins 302′, similar to main portion 301 and fins 302.

[0072] The second peripheral seal 300′ may be formed on the cathode plate 100′, for example by overmolding on the anode plate 100′, or alternatively may be formed on the MEA 200 or formed separately from the anode plate 100′ and the MEA 200. The seal 300′ is ideally made from an elastomeric material and is impermeable to the anode fluid used in the fuel cell 1.

[0073] In particular, the main portion 301' of the second peripheral seal 300' forms a closed loop, which in this example extends along the peripheral region 102' around the entire periphery of the anode plate 100'. Correspondingly, the main portion 301' extends around the entire periphery of the peripheral portion 202, in a closed loop along the peripheral portion 202 of the MEA 200, here in a closed loop along the retaining frame 206. The main portion 301' is interposed between the peripheral region 102' and the peripheral portion 202 in the stacking direction X and seals, over the entire periphery, the space defined between the region 102' and the portion 202 in the stacking direction X. In particular, the main portion 301' surrounds the flow field 103', the homogenization field of the anode plate 100', if present, and the opening for supplying the anode fluid to this side of the anode plate 100', or possibly all openings of the anode plate 100'. The main portion 301' also surrounds the gas diffusion layer 205' and, in turn, the face of the membrane 204' facing in the stacking direction X. The main portion 301' includes two opposing inner longitudinal surfaces 303', which are disposed laterally on either side of the flow field 103'. Each inner longitudinal surface 303' extends along a portion of the main portion 301' parallel to the longitudinal direction Y and faces in the direction of the flow field 103'. Each inner longitudinal surface 303' connects the peripheral region 102' to the peripheral portion 202 in the stacking direction X.

[0074] The main portion 301' of the second perimeter seal 300', the anode plate 100', and the MEA 200 define an anode compartment 40' therebetween. The main portion 301' of the second perimeter seal 300' seals the anode compartment 40' from the exterior of the cell 2, and in particular from the exterior region 3.

[0075] Two bypass regions 50′ belonging to the anode compartment 40′ are defined. Each bypass region 50′ is defined between the anode plate 100′ and the MEA 200 in the stacking direction X, and is defined in the transverse direction Z between the flow field 103′ and the gas diffusion layer 205′ on the one hand and the main portion 301′ of the second peripheral seal 300′ for a portion of the main portion 301′ extending in the longitudinal direction Y on the other hand. Each bypass region 50′ extends along the flow field 103′ in the longitudinal direction Y. The flow field 103′ extends between the two bypass regions 50′ in the transverse direction Z.

[0076] The function of the fins 302' is to reduce or prevent the flow of anode reactant fluid in the longitudinal direction Y in the bypass region 50'. To do this, each fin 302' occludes the cross-section of the bypass region 50' that it occupies, taken perpendicular to the longitudinal direction Y. The fins 302' are disposed along the main portion 301' of the second peripheral seal 300' on one side or the other of the anode bypass region 50', or on both sides. Each fin 302' is attached to one of the inner longitudinal surfaces 303' of the main portion 301' of the second peripheral seal 300'. Each fin 302' extends from the inner longitudinal surface 303' generally along the transverse direction Z toward the flow field 103'. The fins 302' may be formed in one piece with the main portion 301'.

[0077] Each fin 302' includes, in order from a main portion 301', a connecting portion 304', a middle portion 305', and an end portion 306'.

[0078] In the example shown, each fin 302' advantageously has a wall-like shape with an extension in the main plane P, the extension having a broken line profile, a curved line profile or a profile consisting of a combination of one or more straight lines and / or one or more broken lines and / or one or more curves.

[0079] Optionally, each wall-like fin preferably has, at any conceivable point within its extension, a thickness in the longitudinal direction Y, also called width, in a cross section passing through a plane perpendicular to the extension of the wall at this considered point, and a thickness in the stacking direction X, the thickness in the longitudinal direction Y being smaller than the thickness in the stacking direction X, in particular so as to extend from the anode plate 100' to the MEA 200' over at least a portion of the length of the fin 302' in the transverse direction Z, or even over the entire length.

[0080] Alternatively, the thickness in the longitudinal direction Y may be greater than the thickness in the stacking direction X, or may vary depending on the point on the extension being considered.

[0081] Preferably, the connecting portion 304', the intermediate portion 305', and the end portion 306' each have the same width, i.e., the same thickness in the Y direction. In other words, each fin 302' has a substantially constant thickness in the Y direction. This minimizes the amount of material used to form the fins 302', ensures accurate formation of the fins 302', and ensures material continuity, particularly during the manufacturing process of the peripheral seal 300'.

[0082] The fins 302' are connected to the main part 301' via connecting parts 304' extending from the longitudinal inner surface 303'. In the present example, the connecting parts 304' are linear, and their projection onto the main plane P is perpendicular to the longitudinal direction Y, i.e., parallel to the transverse direction Z. The connecting parts 304' are interposed along the stacking direction X between the peripheral region 102' of the anode plate 100' and the peripheral part 202 of the MEA 200.

[0083] An intermediate portion 305' of the fin 302' is attached to the connecting portion 304' and extends it toward the flow field 103'. In this example, the intermediate portion 305' is straight, and its projection onto the main plane P is oblique to the longitudinal direction Y. The intermediate portion 305' is interposed along the stacking direction X between the peripheral region 102' of the anode plate 100' and the peripheral portion 202 of the MEA 200.

[0084] The length of the connecting portion 304' when projected onto the main plane P is preferably shorter than the length of the intermediate portion of the fin 302, for example less than 50% of the length of the intermediate portion 305, preferably less than 30%, and even more advantageously less than 10%.

[0085] The end portions 306' of the fins 302' are attached to the intermediate portion 305' and extend it towards the flow field 103'. The end portions 306' terminate the fins 302'. In this example, the end portions 306' are straight and their projection onto the main plane P is perpendicular to the longitudinal direction Y, i.e. parallel to the transverse direction Z.

[0086] At least a portion of the fin 302', i.e., a contact portion 307' belonging to the end portion 306' of the fin 302' and including the tip of the fin 302', is interposed between the gas diffusion layer 205' and the peripheral region 102' in the stacking direction X. Optionally, another portion of the end portion 306', by which the end portion 306' is attached to the intermediate portion 305', is interposed between the peripheral region 102' and the peripheral portion 202.

[0087] The end portion 306' and the intermediate portion 305' preferably form an angle between 110 degrees, ideally 120 degrees. The intermediate portion 305' and the connecting portion 304' preferably form an angle between 110 and 150 degrees, ideally 120 degrees.

[0088] Thus, according to the embodiment shown in Figures 1 to 4, each fin 302' has, in projection onto the main plane P, an extension path that forms a zigzag from the main portion 301' towards the flow field 103'.

[0089] As shown in FIGS. 2, 3, and 4, the contact portion 307' of the fin 302' is elastically deformed by compression along the stacking direction X between the gas diffusion layer 205' and the peripheral region 102'. This compressive deformation of the contact portion 307' can also deform the intermediate portion 305'. As shown in the cross-sectional view of FIG. 3, the intermediate portion 305' can absorb this deformation of the end portion 306' by twisting slightly. The fact that the intermediate portion 305' is oblique to the longitudinal direction Y advantageously prevents this deformation from being transmitted to the connecting portion 304' and the main portion 301'. Therefore, the specific orientation of the intermediate portion 305' prevents the mechanical stresses associated with the flattening of the contact portion 307' between the layer 205' and the peripheral region 102' from acting on the main portion 301'.

[0090] To illustrate the elastic deformation of the fin 302 during assembly of the cell 2, the same cell 2 is shown in an unassembled state in FIG. 5 . Before assembly of the cell shown in FIG. 5 , the ends 306 and 306' of the seals 300 and 300' are not compressed along the stacking direction X between the gas diffusion layer 205 and the peripheral region 102, and between the gas diffusion layer 205' and the peripheral region 102', respectively. The thicknesses of the contact portions 307 and 307' are the same as those of the other portions of the fins 302 and 302'. FIG. 5 also illustrates a case where the seals 300 and 300' are integral with the plates 100 and 100', respectively, rather than with the MEA 200.

[0091] In practice, in a fuel cell 1, multiple cells 2 similar to those described above are stacked along a stacking direction X, and each cell comprises a cathode plate 100, a first peripheral seal 300, an MEA 200, a second peripheral seal 300', and an anode plate 100'.

[0092] As shown in FIG. 2 , multiple cells 2 are stacked one on top of the other in the stacking direction X, such that the anode plate 100′ of one cell 2 abuts the cathode plate 100 of the next cell 2 in the stacking direction X, and the plates 100′ and 100 of two adjacent cells are stacked in the stacking direction X. The anode plates 100′ and cathode plates 100 of two adjacent cells 2 stacked in this manner form a bipolar plate 10. In the present example, the plates 100 and 100′ of the bipolar plate 10 are attached to each other by, for example, welding or bonding. For example, peripheral regions 102 and 102′ abut each other in the stacking direction X. If necessary, welding or bonding can be performed along the peripheral regions 102 and 102′ around the entire periphery of the bipolar plate 10.

[0093] Because the chemical reaction between the reactant fluids at the membrane 204 is exothermic, it may be desirable to cool the cell. To this end, preferably behind the flow fields 103 and 103', the plates 100 and 100' of the bipolar plate 10 define between them, in the stacking direction X, a flow field 13 for the flow of cooling fluid inside the bipolar plate 10. Where appropriate, welding or gluing between the peripheral regions 102 and 102' provides a seal between the flow field 13 and the exterior of the bipolar plate 10, forming a closed loop surrounding the flow field 13. Preferably, the flow field 13 is supplied with cooling fluid through one of the openings 101 in the plates 100 and 100', i.e., through one of the openings 101c in this example. The cooling fluid is discharged through the other of the openings 101c. The other openings 101a and 101b are sealed from the flow field 13, preventing any reactant fluid from entering the flow field 13. For example, the cooling fluid flows in the longitudinal direction Y through the flow field 13 from one side of the opening 101c to the other.

[0094] Figures 6 and 7 show a second embodiment, which is identical to the first embodiment shown in Figures 1-5, except for the differences noted below. For Figures 1-5 and 6-7, the same reference numerals are used to indicate identical features between the two embodiments. For the embodiment of Figures 6 and 7, reference numerals increased by 200 are used to indicate features that correspond to, but differ from, those described with respect to Figures 1 and 5. The following description will focus on the differences between the embodiment of Figures 6 and 7 and the embodiment of Figures 1-5, and will not describe in detail features that are identical or based on the same principles.

[0095] 6 and 7, the peripheral portion 202 of the MEA 200 is advantageously replaced by a peripheral portion 402. The peripheral portion 402 is preferably formed not by a retaining frame, but by a peripheral continuation 406 that extends the membrane 204 parallel to the main plane P. In this embodiment, the peripheral continuation 406 and the membrane 204 preferably form a single integral membrane, which membrane forms both the central portion 203 and the peripheral portion 202 of the MEA 200.

[0096] 6 and 7, first peripheral seal 500 replaces first peripheral seal 300. First peripheral seal 500 has the same main portion 301 as seal 300, while fins 302 of seal 300 have been replaced by fins 502 for seal 500. Each fin 502 has the same connecting portion 304 and middle portion 305 as fin 302, and further has end portions 506 that replace end portions 306 of fin 302.

[0097] The end portion 506, like the end portion 306, is interposed in the stacking direction X between the gas diffusion layer 205 and the peripheral continuous portion 406, on the one hand, and the peripheral region 102, on the other hand. The end portion 506 is attached to the intermediate portion 305. The end portion 506 is linear. Unlike the end portion 306, the projection of the end portion 506 onto the main plane P is oblique to the longitudinal direction Y, such that the end portion 506 is aligned with and extends the intermediate portion 305. Therefore, the aggregate consisting of the intermediate portion 305 and the end portion 506 is linear, and the projection of the end portion 506 onto the main plane P is oblique to the longitudinal direction Y. The end portion 506 includes a contact portion 507. The contact portion 507 corresponds to the portion of the end portion 506 that is interposed between the gas diffusion layer 205 and the peripheral region 102 in the stacking direction X.

[0098] Thus, according to the embodiment shown in Figures 6-7, each fin 502 has an extension path from the main portion 301 towards the flow field 103 that forms a substantially comma shape.

[0099] In the embodiment shown in Figures 6 and 7, a second peripheral seal 500' preferably replaces second peripheral seal 300'. Peripheral seal 500' has the same main portion 301' as seal 300'. On the other hand, fin 302' of seal 300' has been replaced by fin 502' in seal 500'. Fin 502' has the same connecting portion 304' and the same middle portion 305' as fin 302', and further has end portion 506' that replaces end portion 306' of fin 302'. The features described above for portions 304, 305, 506, and 507 of fin 502 also apply mutatis mutandis to portions 304', 305', 506', and 507' of fin 502'.

[0100] 6 and 7, the anode plate 100′ and the cathode plate 100 are of the same or similar structure to those shown in FIGS. 1 to 5, except that the anode plate 100′ and the cathode plate 100 are not attached to each other by welding or adhesive, but merely abut each other in the stacking direction X and are not attached to each other.

[0101] More precisely, independently of the shape of the fins and the presence of the peripheral continuation 406 or, alternatively, the peripheral portion 402, the plates 100 and 100' in Figures 6 and 7 belong to two adjacent cells 2, respectively, and abut against each other via a plate seal 211 interposed between the plates 100' and 100' belonging to the two adjacent cells in the stacking direction X. The plate seal 211 has a main part 212, which is interposed between the peripheral regions 102 and 102' along the stacking direction X, and forms a closed loop surrounding the flow field 13, preventing leakage of the cooling fluid between the flow field 13 and the outside of the bipolar plate 210 formed by the plates 100, 100' and the plate seal 211. Like seals 300, 300′, 500 and 500′, seal 211 also comprises fins 213 that extend from main portion 212 along transverse direction Z towards flow fields 13, and are arranged between plates 100 and 100′ along stacking direction X. Fins 213 are intended to ensure that cooling fluid flows substantially between flow fields 103 and 103′, rather than between peripheral regions 102 and 102′, thereby improving cooling efficiency.

[0102] Figure 8 shows a third embodiment, which is identical to the first embodiment shown in Figures 1-5, except for the differences noted below. For Figures 1-5 and 8, the same reference numerals are used to indicate features that are identical to those described above. For the embodiment shown in Figure 8, reference numerals increased by 400 are used to indicate features that correspond to, but differ from, those described with respect to Figures 1 and 5. The following description will focus on the differences between the embodiment shown in Figure 8 and that shown in Figures 1-5, and will not describe in detail features that are identical or based on the same principles.

[0103] In the embodiment shown in Figure 8, the first peripheral seal 300 is replaced by a first peripheral seal 700, which has a main portion 301 identical to that of seal 300 and fins 702 which replace fins 302.

[0104] Each fin 702 has a connecting portion 704 that replaces the connecting portion 304, an intermediate portion 305 identical to that of the fin 302, and an end portion 306 identical to that of the fin 302. The connecting portion 704 extends from the main portion 301, from the longitudinal inner surface 303. Like the connecting portion 304, the connecting portion 704 is linear. However, unlike the connecting portion 304, the projection of the connecting portion 704 onto the main plane P is oblique to the longitudinal direction Y. The intermediate portion 305 is attached to and aligned with the connecting portion 704. Therefore, the assembly consisting of the connecting portion 704 and the intermediate portion 305 is linear, and its projection onto the main plane P is oblique to the longitudinal direction Y.

[0105] Figures 9 and 10 show a fourth embodiment, which is identical to the first embodiment shown in Figures 1-5, except for the differences noted below. The same reference numerals are used in Figures 1-5 and 9-10 to indicate the same features as those described above. The following description will focus on the differences between the embodiment of Figures 9-10 and that of Figures 1-5, and will not describe in detail features that are identical or based on the same principles.

[0106] 9 and 10, the peripheral portion 202 of the MEA 200 is replaced by a peripheral portion 402 with a peripheral continuation portion 406 as described for the embodiment shown in Figures 6 and 7. Also, for the embodiment shown in Figures 9 and 10, the anode plate 100' and the cathode plate 100 belong to two adjacent cells, respectively, and are not attached to each other by welding, but only abut against each other in the stacking direction X using the interposed plate seals 211 described above for the embodiment of Figure 6, and are not attached to each other.

[0107] FIG. 11 shows a fifth embodiment, which is identical to the first embodiment shown in FIGS. 1-5, except for the differences noted below. For FIGS. 1-5 and 11, the same reference numerals are used to indicate features that are identical to those described above. For the embodiment shown in FIG. 11, reference numerals increased by 600 are used to indicate features that correspond to, but differ from, those described with respect to FIGS. 1 and 5. The following description will focus on the differences between the embodiment shown in FIG. 11 and that shown in FIGS. 1-5, and will not describe in detail features that are identical or based on the same principles.

[0108] 11, seal 300 is replaced by seal 900, which has the same main portion 301 as seal 300. However, wings 302 are replaced by fins 902. Fin 902 has a connecting portion 904 that replaces connecting portion 304, a middle portion 905 that replaces middle portion 305, and an end portion 906 that replaces end portion 306. These portions 904, 905, and 906 extend from main portion 301 in the direction of flow field 103.

[0109] Generally, the fins 902 are serpentine along an axis parallel to the lateral direction Z.

[0110] The fin 902 is attached to the longitudinal inner surface 303 of the main portion 301 via a connecting portion 904. The connecting portion 904 is not linear like the connecting portion 304 but is curved, and its projection onto the main plane P is also curved with respect to the longitudinal direction Y. Therefore, at least a portion of the connecting portion 904 is oblique to the main portion 301 when projected onto the main plane P.

[0111] The intermediate portion 905 is attached to the connecting portion 904. The intermediate portion 905 is not straight like the intermediate portion 305, but is curved, and its projection onto the main plane P is also curved. The intermediate portion 905 is oblique to the main portion 301 in its projection onto the main plane P, and is preferably oriented at an angle opposite to the connecting portion 904.

[0112] The end portion 906 is attached to the intermediate portion 905 and terminates the fin 302. The end portion 906 is interposed in the stacking direction X between the gas diffusion layer 205 and the retaining frame 206 on the one hand and the peripheral region 102 on the other hand. Unlike the end portion 306, which is straight, the end portion 906 is curved, and its projection onto the main plane P is also curved with respect to the longitudinal direction Y. The end portion 906 is oblique to the main portion 301 in its projection onto the main plane P, and is preferably oriented so as to be oblique in the opposite direction to the intermediate portion 905.

[0113] The end 906 comprises a contact portion 907, which may correspond to the above-mentioned contact portion 307. The contact portion 907 corresponds to a portion of the end 906 that is interposed between the gas diffusion layer 205 and the peripheral region 102 in the stacking direction X.

[0114] Figures 12 and 13 show a sixth embodiment, which is identical to the fourth embodiment shown in Figures 9 and 10, except for the differences noted below. In Figures 12 and 13, the same reference numerals are used to indicate features that are identical to those described above. For the embodiment of Figures 12 and 13, reference numerals increased by 800 are used to indicate features that correspond to, but differ from, features described with respect to Figures 1 and 5. The following description will focus on the differences between the embodiment of Figures 12 and 13 and that shown in Figures 9 and 10, and will not describe in detail features that are identical or based on the same principles.

[0115] 12 and 13, first peripheral seal 300 has been replaced by first peripheral seal 1100. First peripheral seal 1100 has the same main portion 301 as described above. Seal 1100 has fin 1102 that replaces fin 302. Fin 1102 has connecting portion 1104 that replaces connecting portion 304, a middle portion 305 that is the same as that of fin 302, and end portions 306 that are the same as that of fin 302.

[0116] The connecting portion 1104 differs from the connecting portion 304 only in that it comprises an opening 1105 in the form of a notch in the fin 1102, which opening 1105 separates the connecting portion 304 from the peripheral portion 402. To form this opening 1105, the thickness of the connecting portion 1104 measured in the stacking direction X is less than the thickness of the intermediate portion 305 measured in the stacking direction X. The opening 1105 in the longitudinal direction Y allows fluid to flow through the fin 1102, for example to drain reaction products or condensation that may form between adjacent fins 1102.

[0117] In the embodiment shown in Figures 12 and 13, the second peripheral seal 300' is replaced by a peripheral seal 1100'. The peripheral seal 1100' has the same main portion 301' as described above. The peripheral seal 1100' has a fin 1102' that replaces the fin 302'. The fin 1102' has a connecting portion 1104' that replaces the connecting portion 304', a middle portion 305' that is the same as that of the fin 302', and an end portion 306' that is the same as that of the fin 302'. The connecting portion 1104' forms an opening 1105' according to the same principle as the opening 1105 of the connecting portion 1104.

[0118] Figure 14 shows a seventh embodiment, which is identical to the embodiment shown in Figures 12 and 13, except for the differences noted below. In Figure 14, the same reference numerals are used to indicate features that are identical to those described above. For the embodiment shown in Figure 14, reference numerals increased by 200 are used to indicate features that correspond to, but differ from, features described with respect to Figures 12 and 13. The following description will focus on the differences between the embodiment shown in Figure 14 and the previous embodiments, and will not describe in detail features that are identical or based on the same principles.

[0119] In the embodiment shown in FIG. 14, the peripheral seal 1100 ′ has been replaced by the peripheral seal 700 shown in FIG. 8, and the plate seal 211 has been replaced by the plate seal 411 .

[0120] Plate seal 411 comprises a main portion 212 identical to that of plate seal 211. Like plate seal 211, seal 411 further comprises fins 413 which replace fins 213. Fins 413 differ from fins 213 in that they have notches 414 which allow cooling fluid to pass through fins 413 according to the same principle as openings 1105.

[0121] Figure 15 shows an eighth embodiment, which is identical to the first embodiment shown in Figures 1 to 5, except for the differences noted below. In Figure 15, the same reference numerals are used to indicate features that are identical to those described above. The following description will focus on the differences between the embodiment shown in Figure 15 and the embodiments shown in Figures 1 to 5, and will not describe in detail features that are identical or based on the same principles.

[0122] 1 to 5, the embodiment of FIG. 15 includes, in addition to all the elements already described with respect to the embodiment of FIGS. 1 to 5, a dam portion 310, which extends parallel to the main portion 301 of the seal 300, i.e., parallel to the longitudinal direction Y. The dam portion 310 is interposed between the peripheral region 102 and the diffusion layer 205 along the stacking direction X. The dam portion 310 is arranged between the flow field 103 and the seal 300 in the transverse direction Z. The dam portion 310 advantageously connects all or some of the fins 302 to one another, with the respective ends 306 of each fin 302, or at least some of the fins 302, attached to the dam portion 310. Preferably, the dam portion 310 is made of the same material as the seal 300, so that it can be formed at the same time, from the same material, and / or from the same piece as the seal 300.

[0123] Since the dam section 310 surrounds the flow field 103, it is intended to define a channel 295, preferably additional to the channels 105 and having the same function as these channels 105. The channel 295 is defined in the stacking direction X by the peripheral region 102, which performs the same function as the channel bottom 1051 for the channels 105, and by the layer 205. Thus, the channel 295 is defined in the lateral direction Z by the channel tooth 1052 of the cathode plate 100 and the dam section 310, which extends adjacent to and parallel to the channel tooth 1052. The channel tooth 1052 may be referred to as the last channel tooth. Thus, the additional channel 295 is preferably designed to direct the flow of reactant fluids toward the active area of ​​the MEA 200, which is the central portion 203 of the MEA 200, spanning the area where the membrane 204 is accessible to the reactant fluids flowing in the flow field. The presence of the dam portion 310 can simplify the construction of one or more fins 302 attached to the dam portion 310, thereby forming an additional channel, here channel 295, that extends laterally across the entire lateral dimension between the main portion 301 of the peripheral seal 300 and the dam portion 310 and directs reactant fluids across the entire bypass region 40. This is particularly advantageous when the channel teeth 1052 of the flow field 103 are made by pressing the metal cathode plate 100. In this case, it can be complicated to manufacture fins 302 made from a molded polymer material, particularly the fins 302 that contact the last pressed metal tooth using the same material and manufacturing method as the peripheral seal 300. In this case, the presence of the dam portion 310 means that the last channel tooth in the active region is not pressed, but is formed by a tooth of the same material as the peripheral seal 300 and fin 302, forming a single unit.

[0124] 15, the dam portion 310 is positioned opposite the central portion 203 of the MEA 200 at its boundary with the peripheral portion 202 in the stacking direction X, such that the flow path 295 faces the central portion 203. In other words, the dam portion 310 is offset toward the inside of the cell along the lateral direction Z relative to the inner peripheral edge of the frame 206 where the frame 206 holds the membrane 204.

[0125] 16 and 17 show a ninth embodiment, which is the same as the eighth embodiment shown in FIG. 15 except for the following differences.

[0126] In this embodiment, the same reference numerals as in Figure 15 are used. In this embodiment of Figures 16 and 17, the dam portion 310 is offset in the transverse direction Z towards the outside of the cell 2 compared to the dam portion 310 in Figure 15. In other words, the dam portion 310 in Figures 16 and 17 faces the boundary between the peripheral portion 202 and the central portion 203 in the stacking direction X, i.e., faces the inner peripheral edge of the frame 206 that clamps the central portion 203. The channel 295 therefore faces the part of the central portion 203 that runs directly alongside the frame 206. In this case, the objective is to position the dam portion 310 as close as possible to the last channel tooth in the transverse direction Z.

[0127] The flow path 295 defined by the dam portion 310 is not necessarily the same size as the flow path of the flow field 103, and in the case of Figures 16 and 17 in particular, attempts may be made to minimize its size, particularly in the lateral direction Z.

[0128] In a variant not shown, the fins of the first peripheral seal 300, 500, 700, 900, 1100 may not face the fins of the second peripheral seal 300′, 500′, 1100′, but may be offset from one another in the longitudinal direction Y. Also, according to another variant not shown, the same first peripheral seal 300, 500, 700, 900, 1100 or second peripheral seal 300′, 500′, 1100′ may be provided with fins of different shapes, and further, the first peripheral seal 300, 500, 700, 900, 1100 may have fins of a different shape than the second peripheral seal 300′, 500′, 1100′.

[0129] Any feature described with respect to one of the embodiments or variations may be implemented in the other embodiments and variations described above. In particular, any fin and any main portion of the peripheral seal or plate seal may be used in the other peripheral seal or plate seal described above. The dam portion 310 may be applied to any of the peripheral seals or plate seals described above. In particular, the fins may include both curved and straight portions.

Claims

1. A peripheral seal (300, 500, 700, 900, 1100) for a cell (2) for a fuel cell (1), said peripheral seal (300, 500, 700, 900, 1100) comprising: A main portion (301), the main portion (301) being arranged along the stacking direction (X) of the fuel cell, a peripheral region (102) belonging to a plate (100) of said cell (2), said plate (100) extending parallel to a main plane (P) of said cell (2), said main plane (P) being perpendicular to said stacking direction (X), said plate (100) comprising a flow field (103) for reactant fluids surrounded by said peripheral region (102); a main portion (301) configured to be interposed between a peripheral portion (202, 402) belonging to a membrane electrode assembly (200), the peripheral portion (202, 402) further including at least one gas diffusion layer (205); at least one fin (302, 502, 702, 902, 1102), wherein the fin (302, 502, 702, 902, 1102) includes a connecting portion (304, 704, 904, 1104), and the fin (302, 502, 702, 902, 1102) is attached to the main portion (301) via the connecting portion (304, 704, 904, 1104); A peripheral seal (300, 500, 700, 900, 1100) comprising: At least one of the fins (302, 502, 702, 902, 1102) further comprises: an end (306, 506, 906) that terminates the fin (302, 502, 702, 902, 1102), the end (306, 506, 906) being configured to be interposed between the gas diffusion layer (205) and the peripheral region (102) in the stacking direction (X); an intermediate portion (305, 905, 1105) connecting the connecting portion (304, 704, 904, 1104) to the end portion (306, 506, 906), the intermediate portion (305, 905, 1105) being configured to be oblique to the main portion (301) of the peripheral seal (300, 500, 700, 900, 1100) in projection onto the main plane (P); A peripheral seal (300, 500, 700, 900, 1100) comprising:

2. 2. The peripheral seal (300, 500, 700, 900, 1100) of claim 1, wherein the peripheral seal (300, 500, 700, 900, 1100) comprises a plurality of fins (302, 502, 702, 902, 1102), each fin (302, 502, 702, 902, 1102) being connected to the main portion (301) only via the connecting portion (304, 704, 904, 1104).

3. 3. The peripheral seal (300, 500, 700, 900, 1100) according to any one of claims 1 to 2, wherein the connecting portion (304, 1104) is configured to extend perpendicular to the main portion (301) when projected onto the main plane (P).

4. 4. The peripheral seal (300, 500, 700, 900, 1100) according to any one of claims 1 to 3, wherein the end (306) is configured to extend perpendicular to the main portion (301) when projected onto the main plane (P).

5. 5. The peripheral seal (300, 500, 700, 1100) of claim 1, wherein at least a portion of the end portion (306, 506), the intermediate portion (305, 1105) and the connecting portion (304, 704, 1104) are configured to be linear when projected onto the main plane (P).

6. 6. The peripheral seal (900) of claim 1, wherein a portion of the fins (902) of the peripheral seal (900) is configured to be curved in projection onto the main plane (P).

7. The peripheral seal (1100) of any one of claims 1 to 6, wherein the connection (1104) has openings (1105) that allow fluid to flow through the fins (1102).

8. 8. The peripheral seal (300, 500, 700, 900, 1100) of claim 1, wherein the main portion (301) and the fins (302, 502, 702, 902, 1102) of the peripheral seal (300, 500, 700, 900, 1100) are formed in one piece.

9. 9. The peripheral seal (300) according to claim 1, further comprising a dam portion (310), the dam portion (310) being parallel to the main portion (301), the dam portion (310) connecting the ends (306) of the plurality of fins (302), the dam portion (310) being formed in one piece together with the first peripheral seal (300), and the dam portion (310) being configured to be interposed between the gas diffusion layer (205) and the electrode plate (100) along the stacking direction (X).

10. A cell (2) for a fuel cell, the cell (2) comprising a plate (100) and a peripheral seal (300, 500, 700, 900, 1100) according to any one of claims 1 to 9, the plate (100) comprising: the peripheral region (102); the flow field (103) for the reactant fluids surrounded by the peripheral region (102).

11. The cell (2) further comprises: The membrane electrode assembly (200) extends parallel to the main plane (P) of the cell (2) and is superposed on the first electrode plate (100) in the stacking direction (X), and the peripheral portion (202, 402) facing the peripheral region (102) in the stacking direction (X); a central portion (203) comprising a polymeric proton exchange membrane (204) and flanked by said peripheral portions (202, 402); and The membrane electrode assembly (200) includes at least one gas diffusion layer (205) interposed between the polymer proton exchange membrane (204) and the electrode plate (100) in the stacking direction (X), 11. The cell according to claim 10, wherein the peripheral seal provides a seal against the reactant fluid between, on the one hand, a bypass region of the cell defined inside the cell between the peripheral portion of the membrane electrode assembly and the peripheral region, and, on the other hand, an external region of the cell located beyond the main portion and opposite the bypass region, and wherein at least one of the fins extends into the bypass region.

12. 12. The cell (2) of claim 11, wherein the contact portions (307, 507, 907) of the ends (306, 506, 906) are compressed between the gas diffusion layer (205) and the peripheral region (102).

13. The flow field (103) defines a plurality of flow paths (105) for the flow of the reactant fluid, the flow paths (105) extending along a longitudinal direction (Y) perpendicular to the stacking direction (X), and each flow path (105) a channel bottom (1051) belonging to the flow field (103) and extending parallel to the longitudinal direction (Y); 13. The cell (2) according to claim 10, wherein the cell (2) is partitioned by two channel teeth (1052) belonging to the flow field (103) and extending parallel to the longitudinal direction (Y), the channel teeth (1052) being arranged on either side of the channel bottom (1051), protruding relative to the channel bottom (1051), and each channel tooth (1052) being in contact with the gas diffusion layer (205) in the stacking direction (X).

14. 14. The cell (2) according to claim 13, wherein the channel teeth (1052) further protrude from the peripheral region (102) in the stacking direction (X).

15. 15. A fuel cell (1) comprising cells (2), at least one of which is as defined in any one of claims 10 to 14, and in which the cells (2) are stacked along the stacking direction (X) to form a stack.

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