Fuel cell stack, fuel cell and related vehicle

Abstract

The present application relates to a fuel cell stack comprising a plurality of identical bipolar plates (12) stacked in a stacking direction (A11). Each bipolar plate (12) is formed by two monopolar plates which are placed one on top of the other and together form at least one pocket (20) at one end of the bipolar plate (12). Each pocket (20) has an end opening (28) configured to receive a pin (22) of a fuel cell measurement module (18), any two consecutive bipolar plates (12) stacked end to end.

Description

[0001] The present application relates to a fuel cell stack, a fuel cell including the fuel cell stack, and a vehicle including the fuel cell.

[0002] Fuel cells are used as energy sources in various applications, particularly in electric vehicles. In polymer membrane electrolyte fuel cells (PEMFC), hydrogen is supplied to the anode of the fuel cell, and oxygen is supplied to the cathode as an oxidant. A polymer membrane fuel cell (PEMFC) comprises a membrane electrode assembly (MEA) comprising a non-conductive proton exchange solid polymer electrolyte membrane having an anode catalyst on one side and a cathode catalyst on the opposite side. The membrane electrode assembly (MEA) is sandwiched between a pair of conductive elements called bipolar plates, between which a gas diffusion layer (e.g., made of carbon fiber) is usually inserted. Bipolar plates are generally rigid and heat-conductive. They are primarily used as separators for the chemical substances and possible cooling fluids that form the gaseous reactants of the fuel cell, and they are used as collectors for the anode and cathode. The bipolar plate has a channel with a suitable opening for distributing the gaseous reactants of the fuel cell to the surfaces of the corresponding anode and cathode catalysts and for removing reaction products or residues, particularly water produced at the cathode.

[0003] A membrane electrode assembly sandwiched between two bipolar plates forms a unit cell of a fuel cell, and a plurality of unit cells are stacked to form a fuel cell stack. During operation of a fuel cell, it is advantageous to monitor the unit cells, in particular by measuring the electrical characteristics of the cell.

[0004] For example, US-9 997 792-A1 discloses a fuel cell comprising a battery stack connected to a computer via a cable belt connected to each battery via a connection tongue, the cable being fixed by a harness to press the cable against the connection tongue. However, measurements made with this type of arrangement are not reliable, the battery takes up a large space, and the cable is easily damaged due to mechanical stress such as vibration or expansion generated during battery operation, which shortens its service life.

[0005] DE102021202538A1 describes a fuel cell comprising a cell stack. Each bipolar plate comprises an electrical contact, each of which is configured to receive a mating connector. The electrical contacts are aligned along the stacking axis of the cell, and between each bipolar plate, an insulating element is arranged at the periphery of the membrane electrode assembly to prevent a short circuit between two adjacent bipolar plates, in particular during the connection of the electrical contacts to the mating connector. However, the insulating element, and by extension the stack of bipolar plates, is relatively bulky.

[0006] More specifically, the present application seeks to solve these problems by proposing an improved fuel cell stack which is both compact and more reliable.

[0007] To this end, the present application relates to a fuel cell stack. According to the present application, the stack includes a plurality of bipolar plates identical to each other, each bipolar plate extending along a median plane and stacked along a stacking direction orthogonal to the median plane, and two consecutive bipolar plates form a stacked battery between them. Each bipolar plate is formed by two monopolar plates, which are superimposed and together form at least one pocket at one end of the bipolar plate, each pocket having an end opening configured to receive a pin of a measurement module of a fuel cell, and any two consecutive bipolar plates are stacked end to end.

[0008] By the present application, the end-to-end mounting of the bipolar plates makes it possible to provide pockets, the opening of each pocket having a width measured in the stacking direction and therefore greater than the spacing between two consecutive bipolar plates. It is thus easier to insert a pin into each pocket, and the pins are thicker and therefore more robust, which contributes to the reliability of the stack.

[0009] According to an advantageous but non-mandatory aspect of the present application, such a stack may comprise one or more of the following features alone or in any technically permissible combination:

[0010] – Each pocket is opened through an end opening along a connection direction which is parallel to the longitudinal direction of the stack

[0011] direction, the longitudinal direction being orthogonal to the stacking direction.

[0012] – For any two consecutive bipolar plates, the connection square of each pocket of one bipolar plate

[0013] The direction is opposite to the connection direction of each pocket of the other bipolar plate.

[0014] - Each bipolar plate comprises a connection area in which at least one pocket of the bipolar plate is formed; and

[0015] a connecting region which is located opposite the connecting region relative to the center of the bipolar plate,

[0016] For any two consecutive bipolar plates, the connection area of ​​one bipolar plate is arranged opposite to the matching area of ​​the other bipolar plate along the stacking direction.

[0017] And the stack also includes wedging means interposed between each connection area and the opposing mating area so as to limit deformation of each pocket of the connection area when a pin associated with said pocket is inserted into said pocket.

[0018] - the mating area comprises a protrusion which projects from the plate and extends towards the opposing connection area,

[0019] so as to limit the deformation of each pocket in the connection area when the pin associated with said pocket is inserted into the pocket, thereby forming a wedging device.

[0020] – The wedging device comprises a spacer which is inserted between each connection area and the opposite mating area

[0021] Between domains,

[0022] At the same time each spacer is fastened to the mating area.

[0023] – Each bipolar plate comprises an anode outer surface and a cathode outer surface,

[0024] For a given bipolar plate, the mating area of ​​the bipolar plate includes a spacer fastened on the anode surface of the bipolar plate and a spacer fastened on the cathode surface of the bipolar plate.

[0025] – Each bipolar plate comprises an anode outer surface and a cathode outer surface,

[0026] For a given bipolar plate, the wedging device includes three spacers, two of which are arranged on each side of the mating area of ​​the bipolar plate (on the anode surface of the bipolar plate and on the cathode surface of the bipolar plate), and the third spacer is arranged between the two monopolar plates forming the bipolar plate.

[0027] – The wedging device comprises a spacer which is inserted between each connection area and the opposite mating area

[0028] Between domains,

[0029] For each bipolar plate, a wedging device associated with the plate includes a bridge of material that connects the spacers together, and the wedging device is mounted on the edge of the associated bipolar plate so that the spacers (32) are located on each side of the mating area.

[0030] – The wedging device comprises a spacer which is inserted between each connection area and the opposite mating area

[0031] Between domains,

[0032] The stack further comprises membrane electrode assemblies, each of which is located between two consecutive bipolar plates and extends between a connection region and an opposing mating region associated with the two bipolar plates, and a number of spacers are fastened to the membrane electrode assemblies.

[0033] – The spacers are made of elastomeric material.

[0034] - Each bipolar plate comprises a connection area in which at least one pocket of the bipolar plate is formed; and

[0035] a connecting region which is located opposite the connecting region relative to the center of the bipolar plate,

[0036] For any two consecutive bipolar plates, the connection area of ​​one bipolar plate is arranged opposite to the matching area of ​​the other bipolar plate along the stacking direction.

[0037] And the connection area is divided into two rows, the two rows extend along the stacking direction,

[0038] And for each row, the end openings of the pockets in the row are geometrically supported by an opening plane parallel to the stacking axis, and the mating area associated with the connection area of ​​the row is formed to be indented backward from the opening plane, with a distance from the opening plane between 1 mm and 5 mm, preferably greater than or equal to 2 mm.

[0039] Advantageously, for at least one battery of the stack, the battery comprises:

[0040] - A first plate, comprising:

[0041] Outlying areas, and

[0042] A reactive fluid flow field surrounded by a peripheral region,

[0043] - a membrane electrode assembly, which is stacked on the first electrode plate according to the stacking direction and comprises:

[0044] a peripheral portion opposite to the peripheral region in the stacking direction,

[0045] a central portion comprising a proton exchange polymer membrane, the central portion being surrounded by a peripheral portion, and

[0046] at least one gas diffusion layer, which is interposed between the proton exchange polymer membrane and the flow field of the first plate in the stacking direction, and

[0047] - a first peripheral seal comprising:

[0048] a body portion interposed between the peripheral region and the peripheral part of the membrane electrode assembly in the stacking direction, the body portion surrounding the flow field and the gas diffusion layer associated with the flow field, the body portion providing a seal for the reaction fluid between, on the one hand, a compartment of the cell defined inside the cell between the peripheral part of the membrane electrode assembly and the peripheral region, and, on the other hand, a region outside the cell outside the body portion facing the compartment, and

[0049] fins extending from the body portion into the compartment,

[0050] in:

[0051] - the main body comprises two longitudinal sections, each of which extends parallel to a longitudinal direction orthogonal to the stacking direction, extending along the flow field and arranged on each side of the flow field, the compartment comprises two bypass areas, each bypass area being delimited on the one hand by a respective longitudinal section and on the other hand by

[0052] Between the flow field and the gas diffusion layer related to the flow field,

[0053] - For each longitudinal section, at least one fin extends from the longitudinal section to the corresponding bypass zone

[0054] In the domain,

[0055] – Each fin includes:

[0056] a joining portion, by means of which the fin is attached to the corresponding longitudinal portion,

[0057] an end portion which is interposed between the gas diffusion layer and the peripheral region in the stacking direction, and

[0058] a middle portion connecting the joining portion to the end portion, the middle portion being inclined relative to a transverse direction orthogonal to the stacking direction and the longitudinal direction when projected onto the median plane,

[0059] - For each longitudinal section, one or more fins attached to the longitudinal section are arranged relative to the transverse

[0060] The direction is tilted in the same direction,

[0061] - When the stack is in the operating configuration, the fins attached to the longitudinal section located at the bottom are aligned with the first

[0062] The plates are inclined in the same direction as the flow of the reaction fluid.

[0063] Advantageously, for each peripheral seal, the fins attached to opposite longitudinal portions are inclined in opposite directions relative to the transverse direction.

[0064] The present application also relates to a fuel cell, comprising:

[0065] – Stacking as above,

[0066] – two end plates on either side of the stack, and

[0067] – Multiple modules for measuring battery electrical characteristics, each module contains pins, each pin is connected

[0068] to their pockets.

[0069] Finally, the present application relates to a vehicle comprising at least one fuel cell as described above.

[0070] The present application will be better understood by reading the following description which is given by way of example only and by referring to the accompanying drawings, in which:

[0071] –[ Figure 1 ] Figure 1 is a schematic perspective view of a fuel cell according to a first embodiment of the present invention.

[0072] front and side views;

[0073] –[ Figure 2 ] Figure 2 yes Figure 1 A schematic diagram of a stack of bipolar plates of a fuel cell is shown;

[0074] –[ Figure 3 ] Figure 3 yes Figure 1 The connection between the bipolar plate stack module and the battery of the fuel cell shown

[0075] A schematic perspective view of

[0076] –[ Figure 4 ] Figure 4 The two illustrations a) and b) schematically show Figure 1 The stacking of

[0077] decomposition perspective and perspective representation;

[0078] –[ Figure 5 ] Figure 5 Schematically shows Figure 1 a cross-sectional view of the stack shown;

[0079] –[ Figure 6 ] Figure 6 is a schematic cross-sectional view of a fuel cell stack according to another embodiment;

[0080] –[ Figure 7 ] Figure 7 is a schematic cross-sectional view of a fuel cell stack according to another embodiment;

[0081] –[ Figure 8 ] Figure 8 is a schematic cross-sectional view of a fuel cell stack according to another embodiment;

[0082] –[ Fig. 9 ] Fig. 9 is a schematic cross-sectional view of a fuel cell stack according to another embodiment;

[0083] –[ Fig.10 ] Fig.10 is a schematic cross-sectional view of a fuel cell stack according to another embodiment;

[0084] –[ Fig.11] Fig.11 The two illustrations a) and b) show that according to another embodiment of the present application

[0085] Cases, respectively, belong to Figure 4 The stack and bipolar plates of the fuel cell are shown;

[0086] –[ Fig.12 ] Fig.12 The two illustrations a) and b) schematically show a further embodiment of the present application.

[0087] In one embodiment, details of bipolar plates and a cross section of a stack belonging to the same fuel cell;

[0088] –[ Fig.13 ] Fig.13 Schematically shows Figure 1 a perspective view of the stack shown;

[0089] –[ Fig.14 ] Fig.14 The two illustrations a) and b) respectively show, Fig.13 The details of the stack

[0090] Top view, and Fig.13 A partial cross section of a stack;

[0091] –[ Fig.15 ] Fig.15 The two illustrations a) and b) respectively show, Fig.13 The stacked bipolar

[0092] two opposing sides of the plate; and

[0093] –[ Fig.16 ] Fig.16 The two illustrations a) and b) show an alternative embodiment according to the present application.

[0094] Figure 2. Detail of two bipolar plates belonging to a fuel cell.

[0095] Figure 1 and Figure 2 A fuel cell 10 according to a first embodiment of the present application is shown. The fuel cell 10 comprises a stack 11 of bipolar plates 12 .

[0096] In known manner, each bipolar plate 12 has two opposing outer surfaces: an anode surface and a cathode surface.

[0097] Each bipolar plate 12 is formed by two stacked monopolar plates 13, and the two monopolar plates 13 include a first polar plate 13A (here, a cathode plate) and a second polar plate 13B (here, an anode plate). The first and second polar plates (13A, 13B) are Figure 5The expression "two consecutive monopolar plates 13" refers to two cathode monopolar plates 13A and anode monopolar plates 13B associated with the same bipolar plate 12. The monopolar plates 13 are also simply referred to as "plates 13". In the bipolar plate 12 formed by two superimposed monopolar plates 13, the anode monopolar plate 13B forms the anode surface of the bipolar plate 12, while the cathode monopolar plate 13A forms the cathode surface of the bipolar plate 12.

[0098] The cooling circuit is advantageously arranged between two unipolar plates which are assembled to one another in a sealed manner. Each bipolar plate 12 has a substantially flat shape extending along a median plane P12 .

[0099] In this embodiment, the two monopolar plates 13 associated with the same bipolar plate 12 are made of metal and are welded or bonded together.

[0100] refer to Figure 4 The fuel cell 10 comprises a plurality of cells 14 made in the form of a stack 11 of bipolar plates 12, with the cells 14 being formed between two consecutive bipolar plates 12. The stack 11 thus consists of a plurality of individual cells 14 connected in series. For each individual cell 14, the fuel cell 10 also comprises a membrane electrode assembly 200, which is interposed between the two bipolar plates 12 associated with the cell 14. The membrane electrode assembly is also referred to as MEA 200 for short.

[0101] Therefore, each bipolar plate 12 is common to two adjacent cells 14. Each membrane assembly 200 extends along a median plane P200 parallel to the two median planes P12 associated with the bipolar plates 12, and the membrane electrode assembly 200 is interposed between the bipolar plates 12. The median plane P200 is orthogonal to the stacking axis A11.

[0102] The fuel cell 10 is intended, for example, for use in a motor vehicle, in particular an electric motor vehicle, the electrical energy supplying the engine being substantially, if not entirely, supplied by the fuel cell 10 .

[0103] The bipolar plates 12 are stacked along a stacking direction A11. The stacking direction A11 is orthogonal to a median plane P12 of the stacked bipolar plates 12. In other words, the median plane P12 is a plane transverse to the stacking direction A11. A longitudinal direction L and a transverse direction T are also defined, which together with the stacking direction A11 form an orthogonal coordinate system.

[0104] The fuel cell 10 further comprises two end plates 16, which are arranged on each side of the stack 11. The stack 11 is sandwiched between the two end plates 16 and compressed between the end plates 16 in the stacking direction A11. The end plates 16 are made of aluminum, for example.

[0105] An external fluid circuit (not shown) is connected to the cell 10 at the level of the end plate 16, and the reactant gases are distributed to the membrane electrode assembly 200 on the surface of the bipolar plate 12 through channels arranged on the bipolar plate 12 and organized in a channel network 17 (discussed in detail below) containing a flow field 103 and generally including two homogenization fields 104. For each bipolar plate 12, a center C12 of the bipolar plate is defined, which corresponds here to the center of symmetry of the channel network 17.

[0106] To measure an electrical characteristic of the cells 14, such as the voltage at one or more of the cell 14 terminals, a module 18 for measuring at least one electrical characteristic of the cells 14 is connected to the stack 11 of bipolar plates 12. Each module 18 is used to monitor the state of the stack 11 to adapt the control of the fuel cell system 10.

[0107] Thus, two consecutive monopolar plates 13 belonging to the same bipolar plate 12 are advantageously arranged back to back and form at least one pocket 20 between them on one edge of the bipolar plate (for example, arranged on the edge of one end 21 of the bipolar plate 12 in the longitudinal direction L). Thus, in this example, the end 21 is here an edge of the bipolar plate 12, which extends parallel to the transverse direction T.

[0108] Each pocket 20 is configured to receive a pin 22 of a module 18 for measuring an electrical characteristic of the battery 14 .

[0109] The bipolar plates 12 are identical to each other. Two consecutive bipolar plates 12 are stacked end to end, such as Figure 2 As shown, at least one pocket 20 in every two bipolar plates 12 is flush near the module 18 .

[0110] According to the example shown, each bipolar plate 12 forms exactly two pockets 20 for receiving the pins 22. For each bipolar plate 12, the pockets 20 for receiving the bipolar plate 12 are arranged adjacent to each other, forming a connection area 24A of the bipolar plate 12.

[0111] Each bipolar plate 12 also includes a mating region 24B. The mating region 24B of the bipolar plate 12 is a portion of the bipolar plate 12 where the constituent material of the plate extends, preferably a smooth portion. For each bipolar plate 12, the mating region 24B is symmetrically located opposite the connection region 24A relative to the center C12 of the bipolar plate 12. Therefore, for any two consecutive bipolar plates 12 of the stack 11, the connection region 24A of one of the two plates 12 is arranged relative to the mating region 24B of the other bipolar plate 12 along the stacking direction A11. For any three consecutive bipolar plates 12 of the stack 11, the connection region 24A of one of the two plates 12 (the plate is located between the other two bipolar plates 12 surrounding it along the stacking direction A11) is arranged relative to the mating region 24B of each of the other two bipolar plates surrounding it along the stacking direction A11.

[0112] like Figure 2 As shown, it will be understood that the stack 11 comprises two rows 23 of connection areas 24A, each row 23 extending in a stacking direction A11. The two rows 23 are positioned symmetrically to each other with respect to an axis parallel to the stacking direction A11 and passing through the center C12 of each bipolar plate. In this example, the two rows 23 are located on either side of a transverse plane of the stack, which is orthogonal to the longitudinal direction L. In the example shown, the module 18 is connected only to the connection area located at Figure 2 One of the top rows 23, the other row is unused. In a variant (not shown), other modules (such as module 18) are connected to the other row of connection areas 24A.

[0113] What is valid for one row 23 of the connection region 24A is transferable to the other row 23 of the connection region 24A. In the following, mainly the row 23 to which the modules 18 are connected is described.

[0114] The second pocket 20 makes it possible to measure four wires per group of twenty batteries 14. It is also used to measure impedance.

[0115] More specifically, each pocket 20 is shaped to match the pin 22 .

[0116] For each pocket 20 , when two consecutive unipolar plates 13 are in contact with each other, they jointly define a circumferential wall 26 of the pocket 20 .

[0117] Preferably, each pocket 20 has an open end 28, wherein the circumferential wall 26 has a conical shape. More generally, the open end 28 has a trumpet shape. This shape has the advantage of guiding the pin 22 of the module 18 during its insertion into the pocket 20.

[0118] The open ends 28 of the same row 23 are geometrically supported by an opening plane P28 , which is a plane parallel to the stacking direction A11 , in one example a transverse plane, in other words orthogonal to the longitudinal direction L.

[0119] It should be understood that each pin 22 is inserted into the corresponding pocket 20 according to an insertion movement, which is essentially a translational movement toward the inner volume of the corresponding pocket 20. For each pocket 20, a connection direction D20 is defined, which essentially corresponds to the opposite direction of the insertion movement of the pin 22 in the pocket 20, and is therefore parallel to the insertion movement but in the opposite direction. For each pocket 20 of a given bipolar plate 12, each connection direction D20 is parallel to the median plane P12 of the bipolar plate 12. Therefore, each pocket 20 opens outwardly along the connection direction D20 through the open end 28 of the pocket 20.

[0120] Preferably, the pockets 20 of the same connection area 24A face the same direction, that is, the connection directions D20 associated with the pockets 20 are parallel to each other. Therefore, by extension, for each connection area 24A, the connection direction D20 of each pocket 20 associated with the connection area 24A is also the connection direction of the connection area 24A. For each row 23 of the connection areas 24A, the connection direction D20 associated with the connection area 24A is orthogonal to the opening plane P28 associated with the connection area 24A.

[0121] Preferably, for any two consecutive bipolar plates 12 , the connection direction D20 of each pocket 20 of one bipolar plate 12 is opposite to the connection direction D20 of each pocket 20 of the other bipolar plate 12 .

[0122] Advantageously, the circumferential wall 26 of each pocket 20 has ribs 26B to form a passage of small cross section for the pin 22. The ribs 26B eliminate the function of reinforcing the pocket 20 and make it possible to ensure electrical contact between the pin 22 and the pocket 20 inside it.

[0123] Each module 18 here includes ten aligned pins 22, which are configured to connect ten pockets 20 to the module 18, that is, twenty batteries 14; and additional pins 25 to connect a second pocket 20 of one of the twenty batteries 14, such as Figure 3 As shown. Ten aligned pins 22 are used to measure the voltage of two consecutive batteries 14 between two consecutive pins 22. Preferably, the pins 22, 25 of the module 18 are identical.

[0124] In the illustrated embodiment, each connection area 24A includes two pockets 20 , one of which is associated with a pin 22 of the module 18 and the other of which is configured to receive an additional pin 25 .

[0125] The example shown includes two modules 18, but the fuel cell 10 is not limited to two modules, but may include more modules, such as ten modules 18 to connect two hundred cells 14. Similarly, the number of pins 22 of each module 10 is not limited.

[0126] The additional pins 25 are arranged substantially parallel to the aligned pins 20 and are preferably arranged at the longitudinal ends of the module 18. For example, the additional pins 25 are configured to inject current into the current receiving pockets 20 so that the impedance of twenty batteries 14 can be measured.

[0127] refer to Figure 4 , each bipolar plate 12, and thus the two unipolar plates 13 associated with the bipolar plate 12, comprises an opening 101, a peripheral area 102, a flow field 103 and two homogenizing fields 104. In other words, these elements 101 to 104 are located on two opposite faces of each bipolar plate 12. The flow field 103 and the two homogenizing fields 104 are included in the channel network 17.

[0128] The peripheral region 102 extends to the entire periphery of the bipolar plate 12, and is adjacent to 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 arranged inside the peripheral region 102. The peripheral region 102 extends on a plane perpendicular to the stacking direction A11, that is, on a plane parallel to the median plane P12.

[0129] For each battery 12 of stacking 11, each opening 101 is intended to be used for injecting reaction fluid or cooling fluid, or discharge reaction fluid or cooling fluid.Reaction fluid and cooling fluid are the working fluid of fuel cell 10.Opening 101 has closed profile here, so opening 101 forms the pipeline inside stacking 11, and these pipelines are referred to as "internal manifold".In a modification (not shown), the working fluid of fuel cell 10 is supplied by the pipeline outside stacking 11, and these pipelines are referred to as "external manifold".In this case, opening 101 has open profile.No matter the type of pipeline, the principle of the present application is effective.

[0130] In this example, one row of three openings 101 is located on one side of the electrode plate 13 (here, the cathode plate 13A) relative to the transverse direction T, and the three openings 101 are aligned in the transverse direction T. Another row including another three openings 101 is located on the other side of the electrode plate 13, and another three openings 101 are also aligned in the transverse direction T. Each of the two rows of openings 101 is arranged close to a respective longitudinal end of the electrode plate 13.

[0131] For each reaction fluid or cooling fluid, and therefore for each fluid flow field 103 of the battery 12, an opening 101 forms the fluid supply of the relevant flow field, while another opening symmetrically opposite to the center C12 is used to discharge the fluid of the relevant flow field 103, and these two openings 101 are symmetrically opposite to the center C12 and preferably have a symmetrical geometry according to central symmetry relative to the center C12.

[0132] The flow field 103 extends along the longitudinal direction L between the two homogenizing fields 104, beyond the surface of the plate 13A facing the membrane electrode assembly 200. Each homogenizing field 104 is arranged between the flow field 103 and the opening 101 along the longitudinal direction L. Each homogenizing field 104 generally includes a channel connecting one of the openings 101 to the flow field 103. In the example shown, the channels of the homogenizing field 104 are similar to the channels of the flow field 103 and are formed in the same way, but are oriented differently, here fanning out.

[0133] As an alternative (not shown), the channels of the homogenization field 104 have a different width and / or depth than the channels of the flow field 103. Similarly, the channels of the homogenization field 104 can be made in a different way than the channels of the flow field 103, in particular using different technical methods. For example, the channels of the homogenization field 104 are in the form of ribs applied by adding metal, elastomer or polymer material on a portion of the plate 13, which portion is planar or non-planar, while the channels of the flow field 103 can be made by deep drawing, or vice versa.

[0134] For the cathode plate 13A, the first homogenizing field 104 distributes the reaction fluid from one opening 101 so that it flows through the entire flow field 103 along the longitudinal direction L. The second homogenizing field 104 is used to discharge the reaction fluid distributed over the entire flow field 103 to another opening 101 opposite to the plate 13A, where the reaction fluid is discharged.

[0135] The two openings 101 connected by the flow field 103 and the two homogenization fields 104 are opposite to each other relative to the center C12, in other words, the two openings 101 are symmetrically arranged relative to the center C12. It should be understood that for each flow field 103, two symmetrical openings 101 opposite to the center C12 are associated with the flow field 103, and the two openings 101 serve the flow field.

[0136] For each reaction fluid or cooling fluid, and therefore for each fluid flow field of the cell, the two homogenization fields 104 are preferably symmetrical according to a central symmetry relative to the center C12, both in their geometry and in their channel arrangement.

[0137] In a variant (not shown), the plate 13 does not comprise the homogenization field 104 , the flow field 103 being connected directly to the opening 101 .

[0138] Therefore, on the surface of the plate 13A facing the assembly 200, only one reactive fluid flows from one opening 101 to the opposite opening 101 through the flow field 103 along the longitudinal direction L. For the cathode plate 13A, the reactive fluid is the cathode reactive fluid, such as air or oxygen.

[0139] In the example shown, the membrane electrode assembly 200 (or MEA 200) includes a peripheral portion 202, an opening 201, and a central portion 203. The peripheral portion 202 extends to the entire periphery of the MEA 200 and is adjacent to 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 A11 and parallel to the median plane P12.

[0140] The opening 201 of MEA 200 is made in the membrane electrode assembly 200 for allowing the reaction fluid to flow through the MEA along the stacking direction A11. Each opening 201 extends to an opening 101 of the cathode plate 13A along the stacking direction A11, forming a channel pipe (or manifold) for the working fluid of the fuel cell. In other words, the openings 101 and 201 are opposite to each other along the stacking direction A11. In this example, each opening 201 has the same shape as the opposite opening 101.

[0141] In the stack 11, the openings 101 of the bipolar plates 12 and the openings 201 of the membrane electrode assembly 200 together form a conduit inside the stack 11, also referred to as an "internal manifold". In a variant (not shown), the working fluid of the fuel cell 10 is supplied by conduits outside the stack 11, which are referred to as "external manifolds". In this case, the openings 101 of the bipolar plates 12 have an open profile. Regardless of the type of manifold, the principles of the present application are valid.

[0142] The central portion 203 of the MEA 200 faces the flow field 103 and completely covers the flow field 103 along the stacking direction A11. The peripheral edge of the central portion 203 of the MEA 200 may overlap the inner edge of the peripheral portion 202 of the MEA 200, if applicable.

[0143] refer to Figure 5, the central part 203 of MEA 200 includes a membrane 204, which is a proton exchange polymer membrane. The membrane 204 extends parallel to the median plane P12, faces the flow field 103 in the stacking direction A11, and is substantially flat. The membrane 204 is preferably coplanar with the peripheral part 202 of MEA 200. The membrane 204 can be covered with a catalyst layer on its two surfaces parallel to the median plane P12. In the example shown, the membrane 204 extends beyond the flow field 103, particularly when the central part 203 overlaps a part of the peripheral part 202.

[0144] The membrane 204 of each MEA 200 is located between two gas diffusion layers (GDL) 205. Each diffusion layer 205 extends parallel to the median plane P12 and is interposed between the central portion 203 of the MEA 200 and the opposing plates 13 along the stacking direction A11. The central portion 203 located between the GDLs 205 is considered to extend along the median plane P200.

[0145] The MEA 200 advantageously comprises a holding frame 206 supporting the central portion 203, and more particularly the membrane 204. The holding frame 206 then forms the peripheral portion 202. Figure 5 In the example shown, the holding frame 206 clamps the peripheral edge of the film 204 in the stacking direction A11 to hold the film 204. Then, the holding frame 206 clamps the entire portion of the film 204 overlapping the peripheral portion 202 in the stacking direction A11.

[0146] In a variant (not shown), the same film, such as the film 204, can be provided instead of the retaining frame 206 to form the central portion 203 and the peripheral portion 202. However, the configuration shown is preferred because the retaining frame 206 is stronger, more flexible and more fragile than the film 204. The retaining frame 206 is preferably composed of two half-frames of the same basic shape, which are intended to be flat against each other and are made, for example, of a polymer film, such as polyethylene terephthalate, abbreviated to PET; or polyethylene naphthalate, known as PEN. In the latter case, the two half-frames are assembled to each other, for example by gluing.

[0147] In the example shown, each diffusion layer 205 completely covers the facing central portion 203, more specifically the membrane 204, and advantageously extends beyond the peripheral portion 202, i.e. beyond the inner edge of the membrane 204 clamped by the support frame 206. In particular, the gas diffusion layer 205 abuts against the channel network 17 in the stacking direction A11, and against the membrane 204 in the opposite direction, at least in the region corresponding to the flow chamber 103. The gas diffusion layer 205 is advantageously formed of a porous material, allowing the reaction fluid to diffuse from the channel 17 to the membrane 204 when the cell 14 is in operation, and (if applicable) allowing the reaction products from the membrane 204 to diffuse to the channel 105 for discharge.

[0148] Each pin 22, 25 of the module 18 is designed to facilitate effective and durable electrical contact between the module 18 and its corresponding bipolar plate 12 over time. To this end, each pin 22, 25 of the module 18 has, for example, a shape such that once the pin 22, 25 is inserted into the corresponding pocket 20, the pin 22, 25 exerts two opposing forces on the circumferential wall 26 of the pocket 20. Figure 5 It will be appreciated that when the pins 22, 25 are inserted into the corresponding pockets 20, the two plates 13A and 13B forming the corresponding bipolar plate 12 tend to separate from each other.

[0149] The stack 11 also includes wedging means 30, which are arranged between each connection area 24A and the opposite mating area 24B, in order to limit the deformation of each pocket 20 in the connection area 24A when the pin 22 associated with the pocket 20 is inserted into the pocket 20. More specifically, it is to limit the ability of the plates 13A and 13B to separate during the insertion of the pins 22, 25. Preferably, the wedging means 30 are aligned with each pocket 20 along the stacking direction A11. Preferably, the wedging means 30 are arranged on both sides of the pocket 20 along the stacking direction A11.

[0150] exist Figure 5In the example of , for each bipolar plate 12, the wedging device 30 includes two spacers 32, for example having two opposite faces parallel to the median plane P12, for example in the shape of a parallelepiped. Preferably, each spacer 32 is fastened to the mating area 24B and is therefore inserted between the mating area 24B and the connecting area 24A located opposite. For a given bipolar plate 12, the mating area 24B therefore includes a spacer 32 on the anode surface of the bipolar plate 12 and a spacer 32 on the cathode surface of the bipolar plate 12. In the present example, the spacer is made of an electrically insulating material. In addition, it may be advantageous for the spacer to be made of an elastic material, more specifically an elastomer, and therefore specifically an electrically insulating elastomer. The spacer 32 is here made of polysiloxane (also called silicone) and is fastened to the monopolar plate 13 associated with the bipolar plate before forming the stack 11. For example, a silicone paste is applied to the monopolar plate 13, and the silicone forms the spacer 32 after curing. Specifically, the spacers 32 are preferably made by overmolding on the unipolar plate 13. Therefore, each spacer 32 is advantageously fastened directly to the corresponding mating area 24B by overmolding. Alternatively, the spacers are pre-made, for example, by molding and / or machining, and then the spacers are bonded or nested to the unipolar plate 13 to form the wedging device 30.

[0151] Once the cells 14 are stacked in the operating state of the battery 10, the wedging devices 30 abut against the two opposing bipolar plates 12 or are kept at a very short distance from each of the two opposing bipolar plates 12, each wedging device 30 thus being interposed between the connection area 24A of one of the two bipolar plates 12 and the opposite mating area 24B belonging to the other two bipolar plates 12. In the case where the spacer 32 is made of elastic material, in particular, when the pin 22 or 25 is inserted into the pocket 20, the wedging devices 30 arranged on each side of the connection area 24A associated with the pocket 20 can be elastically deformed to adapt to the passage of the pin into the pocket 20, while resisting, by rebounding, the separation of the portion of the plate 13 associated with the pocket 20 by abutting against the adjacent bipolar plate 12, more particularly by abutting against the opposite mating area 24B.

[0152] The spacing L12 is defined as the distance between two adjacent bipolar plates 12, measured between the median planes P12 of two consecutive bipolar plates 12 parallel to the stacking axis A11. The spacing L12 corresponds to the spacing of the fuel cell 10, in other words, to the average thickness of the cell 14. The spacing L12 is, for example, between 0.8 mm and 1.5 mm.

[0153] According to an example, the thickness of the wedging means 30 (measured parallel to the stacking direction A11) is less than the spacing L12 separating two opposing bipolar plates 12 when the stack is in operation, so as to accommodate the passage of the pin into the pocket 20 despite any slight separation of the plates 13 associated with the pocket 20, while limiting the separation, in particular in order to take into account the geometric tolerances of battery manufacturing and assembly.

[0154] Specifically, the wedging device 30 keeps a certain distance between two adjacent bipolar plates 12, specifically, keeps a certain distance between each connection area 24A and the mating area 24B located opposite. The wedging device 30 prevents direct contact between two adjacent bipolar plates 12, more specifically, prevents direct contact between each connection area 24A and the mating area 24B located opposite.

[0155] Advantageously, in the operating state of the stack 10, the thickness of the wedging device 30 is dimensioned along the stacking direction A11 so as to leave a total dimensional gap along the stacking direction A11 between the wedging device 30 and two adjacent bipolar plates 12. This dimensional gap is preferably less than 100 microns, more preferably less than 50 microns. The dimensional gap between the wedging device and the adjacent bipolar plates 12 is not shown in the figures. Due to the dimensional gap, deviations in the dimensions of the wedging device 30 and the bipolar plates 12 can be accepted without any risk of local deformation of the bipolar plates 12 due to the wedging device being too thick relative to the available space between the connection area 24A and the mating area 24B.

[0156] refer to Figure 5 , in which the stack 11 is shown in cross section, for each pocket 20 of a given connection area 24A, the circumferential wall 26 advantageously comprises flared rims 27A which define the open end 28 of the pocket 20. The flared rims 27A correspond to the edges of the monopolar plates 13A / 13B and extend here parallel to the transverse axis T. When moving away from the bottom 29 of the pocket 20, the flared edges 27A diverge relative to the median plane P12. Each flared edge 27A is part of the peripheral edge of the bipolar plate 12 to which the connection area 24A belongs. The flared edges 27A facilitate the insertion of the pins 22 / 25 corresponding to the pocket 20.

[0157] For each pocket 20, the overall dimension L20 is defined as the maximum distance between the two flared edges 27A of the pocket 20 measured parallel to the stacking axis A11. The overall dimension L20 and the spacing L12 are as follows: Figure 5 The end-to-end mounting of the bipolar plates 12 makes it possible to provide the pockets 20 with an overall dimension L20 greater than the spacing L12 , which facilitates the insertion of the pins 22 , which are thicker and therefore more robust.

[0158] Each mating region 24B comprises a mating edge 27B which extends towards the adjacent flared edge 27A, preferably parallel to the adjacent flared edge 27A belonging to the connection region 24A facing the mating region 24B. Each mating edge 27B is part of the peripheral edge of the bipolar plate 12 to which the mating region 24B belongs. Each mating edge 27B here extends parallel to the transverse direction T.

[0159] exist Figures 5 to 8 In the example shown, the flared edge 27A and the mating edge 27B are aligned with each other along the stacking direction A11. In other words, the flared edge 27A and the mating edge 27B are geometrically carried by the opening plane P28.

[0160] It will be appreciated that the wedging means 30 is used to keep each flared edge 27A at a distance from the adjacent mating edge 27B, which reduces the risk of short circuits between two adjacent bipolar plates 12 .

[0161] like Figure 5 As shown, for each cell 14, the membrane electrode assembly 200 is advantageously clamped by wedging means 30 between the two bipolar plates 12 associated with the cell 14. Figure 5 In the example shown, the retaining frame 206 is clamped between two bipolar plates 12 by the wedging device 30 .

[0162] In general, and including the embodiments described below, one or more spacers 32 may be formed from a portion of a seal of the cell 14. Similarly, one or more spacers 32 may be distinct from the seal, but may be made of the same material as at least one seal in the cell. In both cases, the spacers 32 are then preferably made in the same operation as the seal is formed, such as in the same casting, molding or overmolding operation as the seal, whether the seal is rigidly attached to one of the unipolar plates 13, the MEA 200 or the seal is a free seal.

[0163] Figure 6 A stack 211 is shown according to an alternative embodiment of the present application.

[0164] In alternative embodiments of the present application, elements similar to those in other embodiments have the same reference numerals and operate in the same manner. The differences between each embodiment and the previous embodiment or embodiments will be described below.

[0165] Compared with the stack 11 of the previous embodiment, the bipolar plate 12 is formed by welding or bonding two monopolar plates 13 together in a sealed manner. Figure 6The case of the stack 211 shown is an example in which each bipolar plate 12 is composed of two unipolar plates 13, which are assembled by simple compression of each other, since an additional seal 230 is inserted during assembly, which is arranged between the two unipolar plates 13. The directly mounted seal 230 is schematically and non-limitingly shown by a dashed rectangle.

[0166] exist Figure 6 In the example shown, for each bipolar plate 12, the wedging means 30 comprises three spacers 32, for example made of an elastomeric material, in particular silicone; two of the spacers 32 are arranged on each side of the mating region 24B of the bipolar plate 12, i.e., respectively on the anode surface of the bipolar plate 12 and on the cathode surface of the bipolar plate 12, while the third spacer 32 is arranged between the two cathode and anode plates (13A, 13B) forming the bipolar plate 12, preferably also in the mating region of the bipolar plate 12. Preferably, the three spacers 32 are aligned along the stacking axis A11 so as to be subjected to a compressive force parallel to the stacking axis A11.

[0167] Figure 7 FIG. 3 shows a stack 311 according to a second embodiment of the present application. Compared with the previous embodiment, Figure 7 In the case of the stack 311 shown, the monopolar plates 13A and 13B of each bipolar plate 12 include a protrusion 332 extending a certain distance from the median plane P12 associated with the bipolar plate 12, the protrusion 332 being arranged in the mating area 24B and abutting against the pocket 20 facing the connection area 24A. The protrusion 332 forms a relief on the corresponding face of the bipolar plate 12. Thus, the protrusion 332 forms a wedging device 30. For each bipolar plate 12, the associated monopolar plates 13A and 13B are welded together here. As described above, the size of the protrusion 332 along the stacking direction A11 preferably provides a dimensional gap to accommodate the manufacturing and assembly tolerances of the battery 12.

[0168] The projection 332 is advantageously formed together with the formation of the channel 17, more particularly by stamping. The projection 332 is provided integrally with each monopolar plate 13A / 13B. By extension, the wedging device 30 is here formed integrally with the bipolar plate 12, which is economical and fast to produce.

[0169] Figure 8 4 shows a stack 411 according to a second embodiment of the present application. Compared with the previous embodiment, more specifically Figure 5 Specifically shown is the stack 11 compared to the Figure 8In the case of the stack 411 shown, the spacers 32 of the wedging devices 30 associated with each bipolar plate 12, arranged respectively on the anode surface of the bipolar plate 12 and on the cathode surface of the bipolar plate 12, are connected to each other via material bridges 434. The wedging devices 30 are mounted on the edge of the associated bipolar plate 12, more precisely on the mating edge 27B of the associated bipolar plate 12, so that the spacers 32 are located on each side of the mating area 24B, i.e. on each surface of the bipolar plate 12.

[0170] In the example shown, the material bridge 434 is a flexible wall that connects the spacers 32 to each other. Preferably, the material bridge 434 is formed by a continuous wall and covers the entire mating edge 27B facing the connection area 24A so as to electrically insulate the mating edge 27B from the opposing flared edge or edges 27A.

[0171] Preferably, the material bridge 434 is preformed to lightly grip the mating edge 27B of the bipolar plate 12 and hold the wedging device 30 in place at the mating region 24B during assembly of the stack 511. Advantageously, the wedging device 30 is bonded to the bipolar plate 12.

[0172] In one variant (not shown), the mating area 24B includes an opening, such as a drilled hole, and the wedging device 30 includes protuberances that match the shape of the opening, such as studs that match the drilled hole, the opening and the matching protuberances matching each other by shape matching so as to position the wedging device 30 when the wedging device 30 is installed on the corresponding mating area 24B.

[0173] Fig. 9 5 shows a stack 511 according to a second embodiment of the present application. Compared with the previous embodiment, more specifically Figure 5 Specifically shown is the stack 11 compared to the Fig. 9 In the case of the stack 511 shown, the spacer 32 is fastened to the membrane electrode assembly 200, rather than to the monopolar plates 13A / 13B. In the example shown, the spacer 32 is fastened to the holding frame 206 of the MEA 200. Once the stack 511 is formed, the spacer 32 is located between each connection area 24A and the mating area 24B facing each other, forming a wedging device 30.

[0174] In the example shown, each spacer 32 is located on one side of the membrane electrode assembly 200, preferably on the side facing the mating area 24B, which is used to reduce the deviation of the peripheral portion 202 of the MEA 200 relative to the median plane P200 along the stacking direction A11, thereby reducing the risk of tearing the membrane electrode assembly 200. Preferably, each spacer 32 abuts against the flat portion of the mating area 24B. As described above, the size of the spacer 32 along the stacking direction A11 advantageously provides a dimensional gap to accommodate the manufacturing and assembly tolerances of the battery.

[0175] Fig.10 FIG. 6 shows a stack 611 according to a second embodiment of the present application. Compared with the previous embodiment, in particular, Fig. 9 Specifically shown is the stack 511 compared to the Fig.10 In the case of the stack 611 shown, each spacer 32 includes two half spacers 33, which are fastened to each side of the membrane electrode assembly 200 along the stacking direction A11 respectively, so as to better disperse the force on the membrane electrode assembly 200 and reduce the risk of tearing the membrane electrode assembly 200.

[0176] refer to Fig.11 a), for each bipolar plate 12, the mating region 24B is located opposite to the connection region 24A symmetrically with respect to the center C12 of the bipolar plate 12. The connection region 24A and the mating region 24B each have a profile when projected onto the median plane P12.

[0177] Thus, the contour of the connection region 24A comprises a flared edge 27A, seen here from above, which forms an outer portion 33A of the contour of the connection region 24A. In the example shown, the connection region 24A extends close to one opening 101 of the bipolar plate 12, here one opening 101 being located at the end of one of two rows of three openings 101, the connection region 24A forming an inner portion 34A of the contour of the connection region 24A.

[0178] Similarly, the profile of the mating region 24B includes a mating edge 27B, seen here from above, which forms an outer portion 33B of the profile of the mating region 24B. The mating region 24B extends adjacent to one opening 101 of another row of three openings 101, forming an inner portion 34B of the profile of the mating region 24B.

[0179] Preferably, the inner contour of the connection region 24A is symmetrical with respect to the inner contour of the mating region 24B with respect to the center C12. Therefore, when the two bipolar plates are stacked end to end, the inner contour of the connection region 24A of the first of the two bipolar plates 12 is superimposed on the inner contour of the mating region 24B of the other bipolar plate 12.

[0180] Preferably, the outer contour of the connection region 24A is symmetrical with the outer contour of the mating region 24B with respect to the center C12. Therefore, the monopolar plates 13A and 13B are easy to manufacture.

[0181] exist Fig.11 b) In the example shown, the connection area 24A and the matching area 24B are relative to each other. Fig.11 The bipolar plate 12 of a) is arranged differently, with the connection region 24A and the mating region 24B extending in the middle of the three openings 101 in the corresponding row close to the opening 101 .

[0182] Fig.12 An advantageous variation of the bipolar plate 12 is shown. According to the variation, the outer edge of each mating area 24B is set back from the opening plane P28. In the example shown, the mating area 24B has a notch 34 so that the outer contour 33B of the mating area 24B is set back from the outer contour 33A of the connection area 24A. The shape of the notch 34 is not limited. In the example shown, each mating edge 27B is parallel to the opening plane P28 and maintains a certain distance therefrom. For each mating edge 27B, the distance D28 is defined as the minimum distance parallel to the median plane P12 between the mating edge 27B and the relative opening plane P28. By extension, the distance D28 is also the distance between each mating area 24B and the opening plane P28, in other words, the distance between each mating area 24B and the flared edge 27A.

[0183] exist Fig.12 In the example shown, the outer contour 33B is linear, so the distance D28 is simply the distance between the mating edge 27B and the opening plane D28. In the above embodiment, the distance D28 is zero, or substantially zero.

[0184] By retracting backwards, the opening of the flared edges 27A can be enlarged in the stacking direction A11, which facilitates the insertion of the pins 22 / 25 while maintaining a minimum distance between each flared edge 27A and the mating edge 27B associated with the flared edge 27A, reducing the risk of short circuits, in particular during connection of the module 18.

[0185] Therefore, each mating edge 27B is set back from the opening plane 28 by a distance D28 greater than or equal to 1 mm, or preferably greater than or equal to 2 mm, and preferably less than 5 mm.

[0186] refer to Figures 13 to 15 Another aspect of the present application is described. Particular attention is paid to the seal between the monopolar plate 13 and the membrane electrode assembly 200 within each cell 14 . Fig.13 The stack 11 is partially shown, the monopolar plate 13 , here the cathode plate 13A, and the membrane electrode assembly 200 are visible.

[0187] The cathode plate 13A and the membrane electrode assembly 200 form part of a cell 14, which also includes a peripheral seal 300, also referred to as a first seal, which is interposed between the cathode plate 13A and the MEA 200 along the stacking direction A11. The peripheral seal 300 includes a body portion 301 and fins 302. The peripheral seal 300 is preferably made of an elastomeric material and is impermeable to the cathode fluid used in the fuel cell 10. More generally, the peripheral seal 300 is impermeable to each working fluid in the fuel cell 10.

[0188] refer to Fig.14 b), for each anode plate 13B, the stack 11 includes a peripheral seal 300', which is interposed between the anode plate 13B and the membrane electrode assembly 200 opposite the anode plate 13B. The principles of the present application described with respect to the peripheral seal 300 associated with the cathode plate 13A can be transferred to the peripheral seal 300' associated with the anode plate 13B. The peripheral seal 300 associated with the cathode plate 13A is described below.

[0189] In the example shown, the first peripheral seal 300 is formed on the cathode plate 13A, for example by overmolding on the cathode plate 13A. Alternatively, the peripheral seal 300 is formed on the MEA 200, or even separately from the cathode plate 13A and the MEA 200.

[0190] The main body portion 301 is a bead of material that extends continuously and forms a closed contour, in other words, a closed loop, which in this example extends along the peripheral area 102 to the entire periphery of the plate 13A. The main body portion 301 surrounds the flow field 103, the homogenization field 104 (if provided) and the opening 101 serving the flow field 103. In the example shown, the main body portion 301 has a trapezoidal cross section, but this shape is not limiting. The main body portion 301 comprises two longitudinal portions 301A and 301B, which extend along the flow field 103 and extend parallel to the longitudinal direction L here.

[0191] In the example shown, the main portion 301 of the peripheral seal 300 advantageously surrounds all the openings 101 of the plate 13A. In a variant (not shown), other seals are provided around the openings 101 that do not serve the flow field.

[0192] However, the main body portion 301 surrounds neither the connection region 24A nor the mating region 24B.

[0193] When the cathode plate 13A and the membrane electrode assembly 200 are assembled in the stack 11, the main body portion 301 extends in a closed loop along the peripheral portion 202 (here, along the holding frame 206) over the entire periphery of the peripheral portion 202. The main body portion 301 is interposed between the peripheral region 102 and the peripheral portion 202 along the stacking direction A11 so as to seal the space defined between the peripheral region 102 of the cathode plate 13A and the peripheral portion 202 of the MEA 200 over the entire periphery along the stacking direction A11. The main body portion 301 also surrounds the gas diffusion layer 205 and the surface of the membrane 204 facing the cathode plate 13A.

[0194] When the cathode plate 13A and the membrane electrode assembly 200 are assembled in the stack 11, the main body 301, the cathode plate 13A and the MEA 200 define a compartment 40 (here, a cathode compartment) between them. The main body 301 provides a seal for the cathode compartment 40 relative to the exterior of the cell 14, specifically, the exterior region 3 outside the main body 301 relative to the cathode compartment 40. The connection region 24A and the mating region 24B are located outside the cathode compartment 40, and the pocket 20 remains available for connection to the module 18. Therefore, each cell 14 includes two compartments 40 associated with the cathode plate 13A and the anode plate 13B, respectively, which are used to define the cell 14.

[0195] The main body portion 301 of the first peripheral seal 300 includes two opposing inner longitudinal surfaces 303, each of which is arranged transversely on each side of the flow field 103, and each of which extends on a longitudinal portion 301A or 301B of the main body portion 301, toward the direction of the flow field 103. Each inner longitudinal surface 303 connects the peripheral region 102 of the cathode plate 13A to the peripheral portion 202 of the MEA 200 in the stacking direction A11.

[0196] Each cathode compartment 40 comprises two portions called "bypass regions 50" extending between the peripheral seal and the flow field 103 and connecting the openings 101 serving the flow field 103. More specifically, each bypass region 50 extends between the respective longitudinal portion 301A or 301B and the flow field 103. Schematically, each bypass region 50 corresponds to a bypass path around the flow field 103, along which the reaction fluid flows between the two openings 101 serving the flow field 103.

[0197] Each bypass region 50 is defined along the stacking direction A11 between the cathode plate 13A and the MEA 200 and along the transverse direction T between the flow field 103 and the gas diffusion layer 205 on the one hand and between the main part 301 of the peripheral seal 300 on the other hand, a part of which extends along the longitudinal direction L. Each bypass region 50 extends along the longitudinal direction L along the flow field 103, or even from one homogenization field 104 to another homogenization field. The flow field 103 extends along the transverse direction T between two bypass regions 50.

[0198] The function of the fins 302 is to reduce or even prevent the reaction fluid from flowing in the bypass region 50 along the longitudinal direction L. To this end, each fin 302 at least partially closes the cross section of the bypass region 50 it occupies, which cross section is perpendicular to the longitudinal direction L. The fins 302 are distributed in one or the other or both cathode bypass regions 50 along the main body 301 of the seal 300. Each fin 302 is attached to an inner surface 303 of the main body 301. In the example shown, the fins 302 protrude from each longitudinal portion 301A and 301B of the main body 301. Each fin 302 extends from the inner surface 303 as a whole in the transverse direction T and in the direction of the flow field 103. Preferably, the fins 302 are formed integrally with the main body 301.

[0199] Each fin 302 includes a junction part 304 , a middle part 305 , and an end part 306 in order from the main body part 301 .

[0200] In the example shown, each fin 302 is advantageously in the form of a wall having, in a plane, an extension (elongation) on the median plane P12 between its joining portion 304 and its end portion 306, the extension having a rectilinear, folded-line or curved profile, or a profile consisting of one or more straight lines and / or one or more folded lines and / or one or more curves.

[0201] The fin 302 is connected to the main body 301 via a joint portion 304 extending from the inner surface 303. In this example, the joint portion 304 is linear, and its projection on the median plane P12 is perpendicular to the longitudinal direction L, that is, parallel to the transverse direction T. The joint portion 304 is interposed between the peripheral region 102 of the electrode plate 13 and the peripheral portion 202 of the MEA 200 along the stacking direction A11.

[0202] The middle portion 305 of the fin 302 is attached to the joining portion 304 and continues to extend in the direction of the field 103. In the present example, the middle portion 305 is rectilinear and its projection on the median plane P12 is inclined relative to the longitudinal direction L. The middle portion 305 is interposed between the peripheral area 102 and the peripheral portion 202 along the stacking direction A11. In a variant, it can be provided that the middle portion 305 is parallel to the longitudinal direction L, i.e. parallel to the main portion 301. More generally, the middle portion 305 is inclined relative to the transverse direction T, i.e. inclined relative to the orthogonal direction of the longitudinal portion 301A or 301B to which the corresponding fin 302 is attached.

[0203] The end portion 306 of the fin 302 is attached to the middle portion 305 and continues in the direction of the field 103. The end portion 306 terminates the fin 302. In the present example, the end portion 306 is rectilinear and its projection on the median plane P12 is perpendicular to the longitudinal direction L, ie parallel to the transverse direction T.

[0204] At least a portion of the end portion 306 of the fin 302 (referred to as the contact portion 307, including the free end of the fin 302) is interposed between the gas diffusion layer 205 and the peripheral region 102 in the stacking direction A11. If appropriate, another portion of the end portion 306 (through which the end portion 306 is attached to the middle portion 305) is interposed between the peripheral region 102 and the peripheral portion 202.

[0205] In the example shown, the end portion 306 and the middle portion 305 form between them an angle advantageously comprised between 110° and 150°, here 120°. The middle portion 305 and the junction portion 304 form between them an angle advantageously comprised between 110° and 150°, here 120°.

[0206] like Fig.14As shown in Fig. 2, the contact portion 307 of the fin 302 is elastically deformed when it is compressed along the stacking direction A11 between the gas diffusion layer 205 and the peripheral region 102. Since the contact portion 307 is thus compressed, the thickness measured along the stacking direction A11 is less than the thickness of the rest of the fin 302, specifically less than the thickness of the joint portion 304 and the middle portion 305. In the undeformed state of the fin 302, it can be provided that the portion 307 initially has the same thickness as the rest of the fin 302 along the stacking direction A11. This deformation of the contact portion 307 under compression also deforms the middle portion 305. As shown in the figure, the middle portion 305 bears the deformation of the end portion 306 by slightly twisting. The fact that the middle portion 305 is inclined relative to the transverse direction T prevents the mechanical stresses associated with the flattening of the contact area 307 between the layer 205 and the peripheral region 102 from being applied to the main body portion 301, which would have an adverse effect on the sealing properties of the peripheral seal 301 and / or its life.

[0207] Under certain conditions of use of the fuel cell 10, in particular during a cold start of the fuel cell 10, condensation of water vapor into liquid water may occur in the compartment 40. When the fuel cell 10 is in use, for example in a vehicle, the stack 11 is usually placed horizontally, i.e. when the vehicle is parked on a horizontal surface, the stacking direction A11 is substantially horizontal, while the transverse direction T of the stack is substantially vertical. Then, the two longitudinal portions 301A and 301B are horizontal, with one longitudinal portion 301A / 301B of the peripheral seal 301 being located above the other longitudinal portion 301B / 301A of the peripheral seal 301. In Fig.13 and 15 In the example shown in a, Fig.13 A longitudinal portion 301A of the bottom peripheral seal 301 is located below another longitudinal portion 301B of the same peripheral seal 301. Condensed water then tends to accumulate on the same longitudinal portion 301A or 301B of the bottom peripheral seal 301.

[0208] exist Fig.13 and 15 a) shows an example where the cathode plate 13A is visible and it is assumed that the cathode fluid flows from Fig.13 One of the openings 101 on the left side flows to the Fig.13 For example, the reaction fluid flows from the opening 101 at the upper left of the cathode plate 13A to the opening 101 at the lower right. Therefore, the reaction fluid flows along the bypass region 50 in the same direction as a whole (here, rightward along the longitudinal direction L). The circulation of the reaction fluid along the bypass region 50 is determined by Fig.15 The two arrows 51A and 51B in a) are schematically indicated.

[0209] The fins 302 of the bottom longitudinal section 301A are advantageously oriented in the flow direction of the reaction fluid flowing in the bypass zone 50 associated with the bottom longitudinal section 301A, so as to facilitate the discharge of condensed water entrained by the reaction fluid. In other words, the fins 302 of the bottom longitudinal section 301A are inclined in the same direction relative to the transverse direction T in the flow direction of the reaction fluid.

[0210] On the other hand, as described above, two consecutive bipolar plates 12 of the stack 11 are stacked end to end. Fig.13 and 15 a, which is equivalent to taking a first bipolar plate 12 with the same orientation as shown in the figure, and then rotating the second bipolar plate 12 180° around the stacking direction A11 - this is equivalent to obtaining symmetry relative to the center C12. In other words, Fig.13 and 15 The longitudinal section 301B shown at the top of a) is at the bottom (this configuration is not shown).

[0211] Advantageously, for each peripheral seal 301, the fins 302 attached to the opposite longitudinal portions 301A, 301B are inclined in opposite directions relative to the transverse direction T, so that even when the bipolar plates 12 are arranged end to end, the fins 302 at the bottom longitudinal portion 301A or 301B are inclined in the direction of flow of the reaction fluid. Thus, the fins 302 attached to the top longitudinal portion 301B are inclined relative to the transverse axis T in the direction opposite to the direction of flow of the reaction fluid.

[0212] Fig.15 The illustrations a) and b) of the same bipolar plate 12 respectively show two opposite sides of the same bipolar plate 12, the illustration a) showing the cathode plate 13A and the illustration b) showing the anode plate 13B. In other words, between the illustrations a) and b), the same bipolar plate 12 is turned upside down by rotating 180° around the transverse axis T, which is at Fig.15 The middle is vertical.

[0213] refer to Fig.15 a) The principle of the present application defined by the cathode plate 13A Fig.15 b) is of course valid, i.e. the fins 302 of the bottom longitudinal section (here the longitudinal section 301B) are inclined in the same direction as the flow direction of the reaction fluid associated with the anode plate 13B with respect to the transverse axis T. Therefore, the fins 302 belonging to the same longitudinal section 301A or 301B are inclined in the same direction with respect to the transverse direction T.

[0214] It should be understood that the inclination direction of the fins 302 belonging to the bottom longitudinal portion 301A is selected according to the flow direction of the reaction fluid along the corresponding bypass area 50. In the example shown, the flow of the reaction fluid crosses on both sides of each bipolar plate 12, which means that when the plates 13A and 13B are seen from the front, the flow is shown in the same direction, as shown in FIG. Fig.15 as shown in a) and b).

[0215] Advantageously, for the peripheral seal 301 of the anode plate 13B, the fins 302 belonging to the opposite longitudinal portions 301A / 301B are inclined relative to the transverse direction T in opposite directions.

[0216] Fig.16 a) and Fig.16 b) shows a peripheral joint 300 comprising two different types of fins 302 and 302", respectively. As before, it is assumed that the reaction fluid flows from left to right.

[0217] exist Fig.16 a), with respect to the fins 302 described above, the end portion 306 is aligned with the middle portion 305, i.e., the assembly formed by connecting the middle portion 305 and the end portion 306 is inclined relative to the transverse direction T. The fins 302 of the bottom longitudinal portion 301A are inclined in the flow direction of the reaction fluid, while the fins 302 attached to the top longitudinal portion 301B are inclined in the direction opposite to the flow direction of the reaction fluid.

[0218] exist Fig.16 b), relative to the fins 302 described above, the joining portion 304 is aligned with the middle portion 305, i.e., the assembly formed by the middle portion 305 and the joining portion 304 is inclined relative to the transverse direction T. The fins 302 of the bottom longitudinal portion 301A are inclined in the flow direction of the reaction fluid, while the fins 302 attached to the top longitudinal portion 301B are inclined in the direction opposite to the flow direction of the reaction fluid.

[0219] The above-described embodiments and modifications can be combined with each other to produce new embodiments of the present application.

Claims

1. A stack (11, 211, ... 611) of fuel cells (10), the stack comprising: - a plurality of mutually identical bipolar plates (12), each bipolar plate extending along a median plane (P12) and stacked along a stacking direction (A11) orthogonal to the median plane, two consecutive bipolar plates (12) forming a stacked cell (14) between them, in: - each bipolar plate (12) is formed by two monopolar plates (13A, 13B), the two monopolar plates (13A, 13B) are superimposed and together form at least one pocket (20) at one end (21) of the bipolar plate (12), each pocket (20) having an end opening (28) configured to receive a pin (22) of a module (18) for measuring a fuel cell, – Any two consecutive bipolar plates (12) are stacked end to end.

2. The stack (11, 211, ... 611) according to claim 1, wherein: – Each pocket (20) is opened through an end opening (28) along a connection direction (D20), wherein the connection direction is parallel to the longitudinal direction (L) of the stack (11), and the longitudinal direction is orthogonal to the stacking direction (A11), – for any two consecutive bipolar plates (12), the connection direction (D20) of each pocket (20) of one bipolar plate is opposite to the connection direction of each pocket of the other bipolar plate.

3. The stack (11, 211, ... 611) according to claim 1 or 2, wherein: - each bipolar plate (12) comprises: a connection area (24A) in which at least one pocket (20) of the bipolar plate is formed; and a mating area (24B) located opposite the connection area (24A) relative to the center (C12) of the bipolar plate (12), – for any two consecutive bipolar plates (12), the connection region (24A) of one bipolar plate is arranged opposite to the mating region (24B) of the other bipolar plate along the stacking direction (A11), The stack also comprises wedging means (30) interposed between each connection area (24A) and the corresponding mating area (24B) so as to limit the deformation of each pocket (20) of the connection area when the pin (22) associated with the pocket is inserted into the pocket.

4. The stack (311) according to claim 3, wherein: – The mating area (24B) comprises a protrusion (332) which projects from the plates (13A, 13B) and extends towards the opposite connection area (24A) so as to limit the deformation of each pocket (20) of the connection area when the pin (22) associated with the pocket is inserted into the pocket, thereby forming a wedging device (30).

5. The stack (11, 211, 411, 611) according to claim 3, wherein: - the wedging means (30) comprise a spacer (30) interposed between each connection area (24A) and the opposite mating area (24B), - Each spacer (30) is fastened to the mating area (24B).

6. The stack (11, 211) according to claim 5, wherein: - Each bipolar plate (12) comprises an anode outer surface and a cathode outer surface, - For a given bipolar plate (12), the mating region (24B) of the bipolar plate includes a spacer (32) secured to the anode surface of the bipolar plate (12) and a spacer (32) secured to the cathode surface of the bipolar plate (12).

7. The stack (211) according to claim 5 or 6, wherein: - Each bipolar plate (12) comprises an anode outer surface and a cathode outer surface, – For a given bipolar plate (12), the wedging device (30) comprises three spacers (30), two of which are arranged on each side of the mating area (24B) of the bipolar plate (12), respectively on the anode surface of the bipolar plate (12) and the cathode surface of the bipolar plate (12), and the third spacer (32) is arranged between the two monopolar plates (13A, 13B) forming the bipolar plate (12).

8. The stack (411) according to any one of claims 5 to 7, wherein: - the wedging means (30) comprise a spacer (30) interposed between each connection area (24A) and the opposite mating area (24B), - for each bipolar plate (12), the wedging means (30) associated with said bipolar plate comprises a material bridge (434) connecting the spacers (32) together, - The wedging device is mounted on the edge (27B) of the associated bipolar plate (12) so that the spacers (32) are located on each side of the mating area (24B).

9. The stack (511, 611) according to claim 3, wherein: - the wedging means (30) comprise a spacer (30) interposed between each connection area (24A) and the opposite mating area (24B), - the stack further comprises a membrane electrode assembly (200), each membrane electrode assembly (200) being located between two consecutive bipolar plates (12) and extending between a connection region (24A) and an opposing mating region (24B) associated with the two bipolar plates, - Some spacers (32) are fastened to the membrane electrode assembly (200).

10. The stack (11, 211) according to any one of claims 5-9, wherein the spacer (32) is made of an elastomeric material.

11. A stack (11) according to any one of the preceding claims, wherein: - each bipolar plate (12) comprises: a connection area (24A) in which at least one pocket (20) of the bipolar plate is formed; and a mating area (24B) located opposite the connection area (24A) relative to the center (C12) of the bipolar plate (12), – for any two consecutive bipolar plates (12), the connection region (24A) of one bipolar plate is arranged opposite to the mating region (24B) of the other bipolar plate along the stacking direction (A11), - the connection area (24A) is divided into two rows (23), the two rows extending in the stacking direction (A11), – For each row, the end opening (28) of the pocket (20) of the row is geometrically supported by an opening plane (P28) parallel to the stacking axis (A11), while the mating area (24B) associated with the connection area (24A) of the row is set back from the opening plane (P28), and the distance (D28) from the opening plane (P28) is between 1 mm and 5 mm, preferably greater than or equal to 2 mm.

12. The stack (11) according to any one of the preceding claims, wherein for at least one battery (14) of the stack, the battery comprises: - A first electrode plate (13A), comprising: The peripheral area (102), and a flow field (103) of a reactive fluid surrounded by a peripheral region (102), - a membrane electrode assembly (200) which is stacked on the first electrode plate (13A) according to a stacking direction (A11), And also includes: a peripheral portion (202, 402) facing the peripheral region (102) along the stacking direction (A11), a central portion (203) comprising a proton exchange polymer membrane (204), the central portion being surrounded by a peripheral portion (202, 402), and at least one gas diffusion layer (205) interposed between the proton exchange polymer membrane (204) and the flow field (103) of the first electrode plate (13A) along the stacking direction (A11), and - a first peripheral sealing member (300) comprising: a main body portion (301) interposed between the peripheral region (102) and the peripheral part (202) of the membrane electrode assembly (200) in the stacking direction (A11), the main body portion surrounding the flow field (103) and the gas diffusion layer (205) associated with the flow field, the main body portion providing a seal for the reaction fluid between, on the one hand, a compartment (40) of the cell (14) defined inside the cell (14) between the peripheral part (202, 402) of the membrane electrode assembly (200) and the peripheral region (102), and, on the other hand, an area outside the cell (14) outside the main body portion (301) facing the compartment (40), and a fin (302) extending from the body portion into the compartment, in: - the body portion (301) comprises two longitudinal portions (301A, 301B), each longitudinal portion extending parallel to a longitudinal direction (L) orthogonal to the stacking direction (A11), extending along the flow field (103) and arranged on each side of the flow field, the compartment (40) comprising two bypass regions (50), each bypass region being defined between a respective longitudinal portion on the one hand and the flow field (103) and a gas diffusion layer (205) associated with said flow field on the other hand, - for each longitudinal portion, at least one fin (302, 302', 302") extends from said longitudinal portion into the respective bypass region (50), – Each fin includes: a joining portion (304) by which the fin is attached to the respective longitudinal portion (301A, 301B), an end portion (306) which is interposed between the gas diffusion layer (205) and the peripheral region (102) in the stacking direction (A11), a middle portion (305) connecting the joining portion (304) to the end portion (306), said middle portion (305) being inclined relative to a transverse direction (T) orthogonal to the stacking direction (A11) and the longitudinal direction (L) when projected onto the median plane (P12), - for each longitudinal section, one or more fins attached to said longitudinal section are inclined in the same direction with respect to the transverse direction, - When the stack is in the operating configuration, the fins attached to the longitudinal portion situated at the bottom are inclined in the same direction as the flow of the reactive fluid associated with the first plate (13A).

13. The stack (11) according to the preceding claim, wherein: - For each peripheral seal, the fins (302, 320', 302") attached to the opposite longitudinal portions (301A, 301B) are inclined in opposite directions relative to the transverse direction (T).

14. A fuel cell (10), comprising: - a stack (11) according to any one of the preceding claims, - two end plates (16) on each side of the stack (11), - a plurality of measurement modules (18), each measurement module being configured to measure an electrical characteristic of the battery (14), each measurement module (18) comprising pins (22), each pin being connected to a corresponding pocket (20).

15. A vehicle comprising at least one fuel cell (10) according to the preceding claim.

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