Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/02—Details
  • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
  • H01M8/0204—Non-porous and characterised by the material
  • H01M8/0206—Metals or alloys
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/24—Grouping of fuel cells, e.g. stacking of fuel cells
  • H01M8/2465—Details of groupings of fuel cells
  • H01M8/247—Arrangements for tightening a stack, for accommodation of a stack in a tank or for assembling different tanks
  • H01M8/248—Means for compression of the fuel cell stacks
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/02—Details
  • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
  • H01M8/023—Porous and characterised by the material
  • H01M8/0234—Carbonaceous material
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/02—Details
  • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
  • H01M8/0247—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the form
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/02—Details
  • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
  • H01M8/0258—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/02—Details
  • H01M8/0271—Sealing or supporting means around electrodes, matrices or membranes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/02—Details
  • H01M8/0271—Sealing or supporting means around electrodes, matrices or membranes
  • H01M8/0276—Sealing means characterised by their form
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
  • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
  • H01M8/04537—Electric variables
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M8/1004—Fuel cells with solid electrolytes characterised by membrane-electrode assemblies [MEA]
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M2008/1095—Fuel cells with polymeric electrolytes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M2250/00—Fuel cells for particular applications; Specific features of fuel cell system
  • H01M2250/20—Fuel cells in motive systems, e.g. vehicle, ship, plane
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02T90/40—Application of hydrogen technology to transportation, e.g. using fuel cells

Definitions

• the present invention relates to a fuel cell stack, as well as a fuel cell comprising such a stack, and a vehicle comprising such a fuel cell.
• Fuel cells are used as a source of energy in various applications, especially in electric vehicles.
• PEMFC polymer membrane electrolyte type
• hydrogen is supplied to the anode of the fuel cell and oxygen is supplied as an oxidant to the cathode.
• Polymer membrane fuel cells comprise a membrane-electrode assembly (MEA for membrane electrode assembly) comprising a solid polymer electrolyte membrane proton exchanger and non-conductive of electricity, having the anode catalyst on one of its faces and the cathode catalyst on its opposite face.
• a membrane-electrode assembly (MEA) is sandwiched between a pair of electrically conductive elements, called bipolar plates, generally with the interposition of gas diffusion layers, made for example of carbon fabric.
• Bipolar plates are generally rigid and thermally conductive. They mainly serve as separators for the chemical species constituting the gaseous reactants of the fuel cell and for any cooling fluid, and they serve as current collectors for the anode and the cathode.
• the bipolar plates have channels provided with suitable openings to distribute the gaseous reactants of the fuel cell on the surfaces of the respective anode and cathode catalysts and to evacuate the products or residues of reaction, in particular water produced at the cathode.
• a membrane-electrode assembly sandwiched between two bipolar plates forms a unit cell of the fuel cell, several unit cells being stacked to form a stack - also called a stack - of the fuel cell.
• US Pat. No. 9,997,792-A1 discloses a fuel cell comprising a stack of cells, connected to a computer by means of a layer of cables connected to each of the cells by connection tabs, the cables being held by a harness in order to press the cables against the connection tabs.
• the measurements carried out with this type of arrangement are unreliable and the battery has a large size, moreover the cables tend to be damaged due to causes mechanical stresses such as vibrations or expansion generated during the operation of the battery, and consequently reduce its lifespan.
• DE102021202538A1 describes, for its part, a fuel cell comprising a stack of cells.
• Each of the bipolar plates include electrical contacts, which are each configured to receive a complementary connector.
• the electrical contacts are aligned along a cell stacking axis, while insulating elements are positioned on the periphery of the membrane-electrode assemblies, between each bipolar plate, to prevent short circuits between two neighboring bipolar plates, in particular when connecting the electrical contacts to the complementary connectors.
• these insulating elements, and by extension the stack of bipolar plates are relatively bulky.
• the invention relates to a fuel cell stack.
• the stack comprises several bipolar plates, which are identical to each other, which each extend along a median plane and which are stacked in a stacking direction orthogonal to the median plane, two consecutive bipolar plates forming between them a cell of the stack.
• Each bipolar plate is formed by two monopolar plates, which are superimposed and which 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 the fuel cell, while any two successive bipolar plates are stacked head to tail.
• the head-to-tail mounting of the bipolar plates makes it possible to provide pockets, therefore the openings each have a width, measured in the direction of the stack, of which greater than an interval between two successive bipolar plates.
• the insertion of the pins in each pocket is thus facilitated, in addition the pins are thicker, therefore more solid, which contributes to the reliability of the stack.
• such a stack can incorporate one or more of the following characteristics taken in isolation or according to any technically admissible combination:
• Each bipolar plate comprises a connection zone, where the at least one pocket of this bipolar plate is formed, and a complementary zone, which is located opposite the connection zone with respect to a center of this bipolar plate, whereas for any two consecutive bipolar plates, the connection zone of one of the two bipolar plates is arranged opposite the complementary zone of the other bipolar plate according to the stacking direction, and that the stack also includes means wedging, which are interposed between each connection zone and the complementary zone opposite, so as to limit the deformations of each pocket of this connection zone when the pin associated with this pocket is inserted into this pocket.
• the complementary zones include bulges which are made projecting from the pole plates and which extend towards the facing connection zones, so as to limit the deformations of each pocket of this connection zone when the pin associated with this pocket is inserted into this pocket, forming the wedging means.
• the wedging means comprise spacers, which are interposed between each connection zone and the complementary zone opposite, while each spacer is fixed to the complementary zone.
• Each bipolar plate comprises an anode external face and a cathodic external face, whereas for a given bipolar plate, the complementary zone of this bipolar plate comprises a spacer fixed on the anode face of this bipolar plate and a spacer fixed on the cathodic face of this bipolar plate.
• the wedging means comprise spacers, which are interposed between each connection zone and the complementary zone opposite, whereas for each bipolar plate, the wedging means associated with this plate comprise bridges of material, which connect the spacers together, and the wedging means are mounted on an edge of the bipolar plate concerned, so that the spacers (32) are located on either side of the complementary zone.
• the wedging means comprise spacers, which are interposed between each connection zone and the facing complementary zone, while the stack also comprises membrane-electrode assemblies, which are each received between two consecutive bipolar plates and which extend between the connection zones and the facing complementary zones associated with these two bipolar plates, and that some of the spacers are fixed to the membrane-electrode assemblies.
• the spacers are made of an elastomeric material.
• this cell comprises:
• the main part comprises two longitudinal portions, which each extend parallel to a longitudinal direction orthogonal to the stacking direction, which run along the circulation field and which are arranged on either side of the circulation field, the compartment including two bypass zones, which are each delimited between, on the one hand, a respective longitudinal portion and, on the other hand, the circulation field and the gas diffusion layer associated with this circulation field,
• At least one fin extends from this longitudinal portion into the corresponding bypass zone
• each fin includes:
• the fins attached to that of the longitudinal portions located at the bottom are inclined in the same direction as a flow of a reactive fluid associated with this first pole plate.
• the fins attached to opposite longitudinal portions are inclined in opposite directions with respect to the transverse direction.
• the invention also relates to a fuel cell, comprising:
• each module comprising pins, which are each connected to a respective pocket.
• the invention finally relates to a vehicle, which comprises at least one fuel cell as described above.
• Figure 1 shows a schematic front and side perspective view of a fuel cell according to one embodiment of the invention
• Figure 2 shows a schematic view of a stack of bipolar plates of the fuel cell of Figure 1;
• Figure 3 shows a schematic perspective view of the connection between the modules and the cells of the stack of bipolar plates of the fuel cell of Figure 1;
• Figure 4 schematically shows, on two inserts a) and b), the stack of Figure 1, shown respectively in partially exploded perspective and in perspective;
• FIG 5 schematically shows a section of the stack of Figure 1;
• Figure 6 schematically shows a section of a stack of a fuel cell according to another embodiment
• FIG 7 Figure 7 schematically shows a section of a stack of a fuel cell according to another embodiment
• Figure 8 schematically shows a section of a stack of a fuel cell according to another embodiment
• Figure 9 schematically shows a section of a stack of a fuel cell according to another embodiment
• FIG. 10 schematically represents a section of a stack of a fuel cell according to another embodiment
• FIG. 11 schematically shows, on two inserts a) and b), a bipolar plate belonging respectively to the stack of Figure 4 and to a fuel cell conforming to another embodiment of the invention;
• Figure 12 schematically shows, on two inserts a) and b), a detail of a bipolar plate and a section of a stack belonging to the same fuel cell according to another embodiment of the invention
• Figure 13 schematically shows a perspective view of the stack of Figure 1;
• Figure 14 shows respectively, on two inserts a) and b), a top view of a detail of the stack of Figure 13 and a section of part of the stack of Figure 13;
• figure 15 represents respectively, on two inserts a) and b), two opposite faces of a bipolar plate of the stack of figure 13, and
• FIG 16 shows, on two inserts a) and b), details of two bipolar plates belonging to fuel cells in accordance with alternative embodiments of the invention.
• FIGS 1 and 2 there is shown a fuel cell 10 according to a first embodiment of the invention.
• the fuel cell 10 comprises a stack 11 of bipolar plates 12.
• each bipolar plate 12 has two opposite outer faces: an anode face and a cathode face.
• Each bipolar plate 12 is here formed by two monopolar plates 13, superimposed, the two monopolar plates 13 including 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 and 13B being visible in FIG. 13B associated with the same bipolar plate 12.
• the monopolar plates 13 are also simply called "polar plates 13". In such a bipolar plate 12 formed by two monopolar plates 13, superimposed, the anode monopolar plate 13B forms the anode face of the bipolar plate 12, and the cathode monopolar plate 13A forms the cathode face of the bipolar plate 12.
• a cooling circuit is advantageously arranged between the two monopolar plates, which are assembled to one another in a sealed manner.
• Each bipolar plate 12 has a substantially planar shape which extends along a median plane P12.
• the two monopolar plates 13 associated with the same bipolar plate 12 are made of metal and are welded or glued to each other.
• the battery 10 comprises a plurality of cells 14 made in the form of a stack 11 of bipolar plates 12, a cell 14 being formed between two consecutive bipolar plates 12.
• a stack 11 thus consists of several individual cells 14 connected in series.
• the fuel cell 10 also comprises a membrane-electrode assembly 200, which is interposed between the two bipolar plates 12 associated with this cell 14.
• the membrane-electrode assembly 200 is also simply called MEA 200.
• Each bipolar plate 12 is thus common to two neighboring cells 14.
• Each membrane assembly 200 extends along a mean plane P200, which is parallel to the two median planes P12 associated with the bipolar plates 12 between which this membrane electrode assembly 200 is inserted.
• the mean plane P200 is orthogonal to the stacking axis A11.
• the fuel cell 10 is for example intended to be used in a motor vehicle, in particular an electric motor vehicle, the electrical energy supplying the motor being essentially, if not entirely, provided by the fuel cell 10.
• the bipolar plates 12 are stacked in a stacking direction A1 1.
• the stacking direction A11 is orthogonal to the median plane P12 of the stacked bipolar plates 12.
• 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 reference.
• the fuel cell 10 also comprises two end plates 16, which are arranged on either side of the stack 11.
• the stack 11 is sandwiched between the two end plates 16 and is compressed along the stacking direction A11 between the end plates 16.
• the end plates 16 are for example made of aluminum.
• External fluidic circuits (not shown) are connected to the cell 10 at the end plates 16 and the reactive gases are distributed to the membrane electrode assemblies 200 on the surface of the bipolar plates 12 via channels provided thereon and organized into a network of channels 17 comprising a circulation field 103, and generally two homogenization fields 104, which will be detailed below.
• a center C12 of this bipolar plate is defined, which here corresponds to a center of symmetry of the network of channels 17.
• modules 18 for measuring at least one electrical characteristic of the cells 14 are connected to the stack 11 of bipolar plates 12. Each module 18 makes it possible to monitor the state of the stack 11 in order to adapt the command and control of the fuel cell system 10.
• Two successive monopolar plates 13, therefore belonging to the same bipolar plate 12, are advantageously arranged back to back and form between them at least one pocket 20 on an edge of the bipolar plate 12, for example on an edge arranged at one end 21 of the bipolar plate 12 in the longitudinal direction L.
• the end 21 is therefore here in this example an edge of the bipolar plate 12, which extends parallel to the transverse direction T.
• Each pocket 20 is configured to receive a pin 22 of a module 18 for measuring the electrical characteristics of the cells 14.
• the bipolar plates 12 are identical to each other. Two successive bipolar plates 12 are stacked head to tail, as shown in Figure 2, so that only at least one pocket 20 of one out of two bipolar plates 12 is flush in the vicinity of the modules 18.
• each bipolar plate 12 forms exactly two pockets 20 for receiving a pin 22 each.
• the pockets 20 for receiving this bipolar plate 12 are arranged close to each other, forming a connection zone 24A of this bipolar plate 12.
• Each bipolar plate 12 also includes a complementary zone 24B.
• the complementary zone 24B of the bipolar plate 12 is a bipolar plate portion 12 in which extends the constituent material of the plate, preferably a smooth portion.
• the complementary zone 24B is located symmetrically opposite the connection zone 24A with respect to the center C12 of this bipolar plate 12.
• the connection zone 24A of one of the two plates 12 is arranged facing, in the stacking direction A11, the complementary zone 24B of the other bipolar plate 12.
• connection zone 24A of one of the two plates 12, which is located between the two other bipolar plates 12 which frame it in the stacking direction A1 1 is arranged facing, in the stacking direction A11 , the zone complementary 24B to each of the two other bipolar plates 12 which surround it in the stacking direction A1 1 .
• the stack 11 comprises two rows 23 of connection zones 24A, each of the rows 23 extending along the stacking direction A1 1.
• the two rows 23 are located symmetrically to one another with respect to an axis parallel to the stacking direction A11 and passing through the center C12 of each of the bipolar plates.
• the two rows 23 are located on either side of a transverse plane of the stack, the transverse plane being orthogonal to the longitudinal direction L.
• the modules 18 are connected to only one of the rows 23, located on the top of figure 2, the other row being left unused.
• other modules of the type of modules 18 are connected to the other row of connection zones 24A.
• connection areas 24A can be transposed to the other row 23 of connection areas 24A.
• the second pocket 20 makes it possible to measure four wires per group of twenty cells 14. It is used for impedance measurement.
• each pocket 20 is shaped to cooperate with said pin 22.
• the two successive monopolar plates 13 together delimit, when they are in contact with one another, a circumferential wall 26 of the pocket 20.
• each pocket 20 has an open end 28 where the circumferential wall 26 has a conical shape. More generally, the open end 28 has a flared shape. Such a shape has the advantage of guiding the pin 22 of a module 18 during its introduction inside said pocket 20.
• the open ends 28 of the same row 23 are geometrically carried by an opening plane P28, which is a plane parallel to the stacking direction A1 1 , in one example a transverse plane, in other words orthogonal to the longitudinal direction L.
• each pin 22 is inserted into the corresponding pocket 20 according to an insertion movement, which is substantially a translational movement, oriented towards an interior volume of the corresponding pocket 20.
• a direction of connection D20 is defined, which corresponds substantially to an opposite direction of the movement of insertion of pin 22 into this pocket 20, therefore a direction parallel to the movement of insertion but oriented in the opposite direction.
• each connection direction D20 is parallel to the plane median P12 of this bipolar plate 12.
• the pockets 20 of the same connection zone 24A are oriented in the same direction, that is to say that the directions of connection D20 associated with these pockets 20 are parallel to each other.
• the connection direction D20 of each pocket 20 associated with this connection zone 24A is also a connection direction for this connection zone 24A.
• the directions of connection D20 associated with these connection areas 24A are orthogonal to the opening plane P28 associated with these connection areas 24A.
• the D20 connection direction of each pocket 20 of one of the two bipolar plates 12 is oriented opposite the D20 connection direction of each pocket 20 of the other bipolar plate 12.
• the circumferential wall 26 of each pocket 20 has a rib 26B so as to form a passage of reduced section for a pin 22.
• the rib 26B plays a role in stiffening the pocket 20, and makes it possible to ensure electrical contact inside the pocket 20 between the pin 22 and the pocket 20.
• Each module 18 here has ten aligned pins 22 configured to connect ten pockets 20 to said module 18, i.e. twenty cells 14, and an additional pin 25 to connect the second pocket 20 of one of the twenty cells 14, as shown in Figure 3.
• the ten aligned pins 22 make it possible to measure between two consecutive pins 22 the voltage of two consecutive cells 14. Pins 22, 25 of a module 18 are preferably identical.
• each connection zone 24A comprises two pockets 20, one of the pockets 20 being associated with one of the pins 22 of the module 18, while the other pocket 20 is configured to receive the additional pin 25.
• the example represented comprises two modules 18, however the fuel cell 10 is not limited to two modules but can comprise more, for example ten modules 18 to connect two hundred cells 14. Similarly, the number of pins 22 for each module 10 is not limiting.
• each bipolar plate 12, and by extension the two monopolar plates 13 associated with this bipolar plate 12, comprises openings 101, a peripheral zone 102, a circulation field 103 and two homogenization fields 104.
• the elements 101 to 104 are found on the two opposite faces of each bipolar plate 12.
• the circulation field 103 and the two homogenization fields 104 are included in the channel network 17.
• the peripheral zone 102 extends over the entire circumference of the bipolar plate 12, and here borders the openings 101, the homogenization fields 104 and the circulation field 103.
• the openings 101, the homogenization fields 104 and the circulation field 103 are arranged inside the peripheral zone 102.
• the peripheral zone 102 extends in a perpendicular plane in the stacking direction A11, i.e. in a plane parallel to the median plane P12.
• Each opening 101 is intended either for the injection of reactive or cooling fluid, or for the evacuation of reactive or cooling fluid, for each cell 12 of the stack 11.
• the reactive and cooling fluids are operating fluids of the fuel cell 10.
• the openings 101 here have a closed contour, also the openings 101 form internal ducts in the stack 11, these ducts being called “internal manifold” in English.
• the operating fluids of the fuel cell 10 are supplied by conduits external to the stack 11, these conduits being called “external manifolds" in English.
• the openings 101 have an open outline. The principles of the invention are valid regardless of the type of ducts
• a row of three openings 101 is located on the one hand of the polar plate 13 - here the cathode plate 13A - with respect to the transverse direction T, the three openings 101 being aligned in the transverse direction T.
• s 101 is provided near a respective longitudinal end of the pole plate 13.
• an opening 101 forms a fluid supply for the circulation field concerned, and another opening, located symmetrically opposite with respect to the center C12, is used for the evacuation of fluid for the circulation field 103 concerned, the two openings 101 located symmetrically opposite with respect to the center C12 being preferably of symmetrical geometries according to a symmetry central with respect to the center C12.
• the circulation field 103 extends, between the two homogenization fields 104 in the longitudinal direction L, on one face of the plate 13A facing in the direction of the membrane-electrode assembly 200.
• Each homogenization field 104 is arranged between the circulation field 103 and the openings 101 in the longitudinal direction L. s 101 to the circulation field 103.
• the channels of the homogenization fields 104 are similar and formed in the same way as those of the circulation field 103, except for their orientation, here fan-shaped.
• the channels of the homogenization fields 104 have a width and/or a depth different from those of the circulation field 103.
• the channels of the homogenization fields 104 can be produced in a different way from those of the circulation field 103, in particular with different technological processes.
• the channels of the homogenization fields 104 are made in the form of ribs applied by adding material, metal, elastomer, or polymer, on a portion of the pole plate 13, this portion possibly being flat or not, while the channels of the circulation field 103 can be made by stamping, or vice versa.
• the first homogenization field 104 makes it possible to distribute the reactive fluid coming from one of the openings 101 so that it circulates throughout the circulation field 103, in the longitudinal direction L.
• the second homogenization field 104 makes it possible to evacuate the reactive fluid distributed over the whole of the circulation field 103 to another opening 101, located opposite the plate 13A, where the reactive fluid is evacuated.
• the two openings 101 connected by the circulation field 103 and the two homogenization fields 104 are located opposite each other with respect to the center C12, in other words these two openings 101 are arranged symmetrically with respect to the center C12. It is understood that for each circulation field 103, two openings 101 symmetrical opposite with respect to the center C12 are associated with this circulation field 103, these two openings 101 serving this circulation field.
• the two homogenization fields 104 are preferably symmetrical according to a central symmetry with respect to the center C12, both in the geometry of the homogenization fields 104 and in the arrangement of the channels of the homogenization fields 104.
• the pole plates 13 do not include the homogenization fields 104, the circulation field 103 being directly connected to the openings 101.
• the reactive fluid is cathodic reactive fluid, for example air or oxygen.
• the membrane-electrode assembly 200 - or MEA 200 - comprises a peripheral portion 202, openings 201, and a central portion 203.
• the peripheral portion 202 extends over the entire circumference of the MEA 200, and borders the openings 201 and the central portion 203, which are located inside the peripheral portion 202.
• the openings 201 have an outline closed.
• the peripheral portion 202 extends in a plane perpendicular to the stacking direction A11, parallel to the median plane P12.
• the openings 201 of the MEA 200 are made in the membrane electrode assembly 200 to allow the circulation of reactive fluids through the MEA in the stacking direction A11.
• Each opening 201 extends one of the openings 101 of the cathode pole plate 13A along the stacking direction A11, forming passage ducts - or manifolds in English - for the operating fluids of the fuel cell.
• the openings 101 and 201 are opposite in the stacking direction A11.
• each opening 201 has the same shape as the opening 101 with which it is opposite.
• the openings 101 of the bipolar plates 12 and the openings 201 of the membrane-electrode assemblies 200 together form ducts internal to the stack 11, also called “internal manifold” in English.
• the operating fluids of the fuel cell 10 are supplied by conduits external to the stack 11, these conduits being called “external manifolds" in English.
• the openings 101 of the bipolar plates 12 each have an open outline. The principles of the invention are valid regardless of the type of ducts.
• the central portion 203 of the MEA 200 is facing the circulation field 103 and completely covers the circulation field 103 according to the stacking direction A11.
• a peripheral perimeter of the central portion 203 of the MEA 200 can optionally overlap an inner perimeter of the peripheral portion 202 of the MEA 200.
• 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 the median plane P12, facing the circulation field 103 along the stacking direction A11, and is substantially flat.
• the membrane 204 is preferentially coplanar with the peripheral portion 202 of the MEA 200.
• the membrane 204 can be covered with a layer of catalyst on its two faces parallel to the median plane P12. In the example illustrated, the membrane 204 extends beyond the circulation field 103, in particular in the case where the central portion 203 overlaps part of the peripheral portion 202.
• each MEA 200 is caught between two gas diffusion layers 205, also called GDL, an acronym for “Gas Diffusion Layer”.
• GDL gas diffusion layers
• 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 opposite polar plate 13, in the stacking direction A11.
• the central portion 203, taken between the GDL205, is considered to extend along the mean plane P200.
• the MEA 200 advantageously comprises a retaining frame 206 to support the central portion 203, in particular to support the membrane 204.
• the retaining frame 206 then forms the peripheral portion 202.
• FIG. re then the entire part of the membrane 204 which overlaps the peripheral portion 202 according to the stacking direction A11.
• the holding frame 206 is preferably made up of two half-frames of substantially identical shapes which are intended to come into plane bearing against each other, and which are, for example, made of polymer film, for example of poly(ethylene terephthalate), known by the abbreviation PET, or poly(ethylene naphthalate), known by the abbreviation PEN. In the latter case, the two half-frames are for example assembled to each other by gluing
• each diffusion layer 205 completely covers the facing central portion 203, in particular covers the membrane 204, and advantageously overflows the peripheral portion 202, namely the inner periphery of the retaining frame 206 pinching the membrane 204.
• the gas diffusion layer 205 is, at least in the zone corresponding to the circulation chamber 103, resting on the network of channels 17 along the stacking direction A11, and resting against the membrane 204 in the opposite direction.
• the gas diffusion layer 205 is advantageously formed of a porous material, and allows the reactive fluid to diffuse from the channels 17 to the membrane 204 when the cell 14 is in operation, and possibly reaction products from the membrane 204 to diffuse to the channels 105 to be evacuated.
• each pin 22, 25 of the module 18 is designed to promote effective and durable electrical contact over time between the module 18 and the bipolar plate 12 to which it corresponds.
• each pin 22, 25 of the module 18 has for example a shape such that the pin 22, 25 exerts two opposing forces on the circumferential wall 26 of the pocket 20 once the pin 22, 25 has been inserted into the corresponding pocket 20. Referring to Figure 5, it is understood that when the pins 22, 25 are inserted into the corresponding pockets 20, the two polar plates 13A and 13B which form the corresponding bipolar plate 12 tend to move away from each other.
• the stack 11 also comprises wedging means 30, which are arranged between each connection zone 24A and the complementary zone 24B opposite, so as to limit the deformations of each pocket 20 of this connection zone 24A when the pin 22 associated with this pocket 20 is inserted into this pocket20. , in particular so as to limit the ability of these pole plates 13A and 13B to move apart during the insertion of the pins 22, 25.
• the wedging means 30 are aligned, along the stacking direction A11, with each of the pockets 20.
• the wedging means 30 are arranged on either side of each pocket 20 according to the stacking direction A11.
• the wedging means 30 comprise two spacers 32, having for example two opposite faces parallel to the median plane P12, for example of parallelepiped shape.
• each spacer 32 is fixed to the complementary zone 24B, and is thus interposed between this complementary zone 24B and the connection zone 24A located opposite.
• the complementary zone 24B thus comprises a spacer 32 on the anode face of this bipolar plate 12 and a spacer 32 on the cathode face of this bipolar plate 12.
• the spacers are made of electrically insulating material.
• the spacers 32 may be made of an elastic material, in particular of elastomer, therefore in particular of electrically insulating elastomer.
• the spacers 32 are here made of polysiloxane, also called silicone, and are fixed on the monopolar plates 13 associated with this plate bipolar, before forming the stack 11.
• polysiloxane also called silicone
• the spacers 32 are advantageously made by overmolding on the monopolar plates 13.
• each spacer 32 is advantageously fixed directly, by overmolding, to the corresponding complementary zone 24B.
• spacers are manufactured beforehand, for example by molding and/or by machining, these spacers then being glued or fitted onto the monopolar plates 13, and thus forming the wedging means 30.
• the wedging means 30 bear against the two opposite bipolar plates 12, or at a very short distance from each of the two opposite bipolar plates 12, each wedging means 30 thus being interposed between a connection zone 24A of one of the two bipolar plates 12, and the complementary zone 24B located opposite and belonging to the other two bipolar plates 1 2.
• the wedging means 30 arranged on either side of the connection zone 24A associated with this pocket 20 can be caused to deform elastically to accommodate the passage of the pin in the pocket 20, while resisting, by elastic return, the separation of the associated pole plates 13 to this pocket 20, by bearing against the neighboring bipolar plates 12, in particular by bearing against the complementary zones 24B facing each other.
• An interval L12 is defined as being a distance between two neighboring bipolar plates 12, measured between the median planes P12 of two successive bipolar plates 12 parallel to the stacking axis A11.
• the interval L12 corresponds to the pitch - also called "pitch" in English - of the fuel cell 10, in other words to the average thickness of a cell 14.
• the interval L12 is typically between 0.8 mm and 1.5 mm.
• the wedging means 30 have a thickness, measured parallel to the stacking direction A11, less than the interval L12 separating the two facing bipolar plates 12 in the operational state of the battery, to allow despite any slight separation of the polar plates 13 associated with this pocket 20 to accommodate the passage of the pin in the pocket 20, while limiting this separation, in particular in order to take account of geometric tolerances cell manufacturing and assembly.
• the wedging means 30 keep the two neighboring bipolar plates 12 at a distance, in particular keep each connection zone 24A from the complementary zones 24B located opposite.
• the wedging means 30 avoid any direct contact between the two neighboring bipolar plates 12, in particular avoid any direct contact between each connection zone 24A and the complementary zones 24B located opposite.
• the wedging means 30 are dimensioned in thickness, along the stacking direction A11, so as to provide, between the wedging means 30 and the two neighboring bipolar plates 12, a total dimensional clearance along the stacking direction A11.
• This dimensional clearance is preferably less than 100 microns, more preferably less than 50 microns.
• the dimensional clearance between the wedging means and the neighboring bipolar plates 12 is not shown in the figures. Thanks to this dimensional play, it is possible to accept dimensional dispersions of the wedging means 30 and of the bipolar plates 12 without risking that the wedging means, which would be too thick compared to the space available between a connection zone 24A and the complementary zones 24B, cause local deformation of the bipolar plates 12.
• the circumferential wall 26 advantageously comprises flared edges 27A, which delimit the open end 28 of this pocket 20.
• the flared edges 27A correspond to the edges of the monopolar plates 13A / 13B and extend here parallel to the transverse axis T.
• the edges 27A diverge with respect to the median plane P12 as one moves away from a bottom 29 of this pocket 20.
• Each flared edge 27A is a portion of an outer edge of the bipolar plate 12 to which this connection zone 24A belongs.
• the flared edges 27A facilitate the insertion of the pin 22/25 corresponding to the pin 20 considered.
• a space requirement L20 is defined as being a maximum distance, measured parallel to the stacking axis A11, between the two flared edges 27A of this pocket 20.
• the space requirement L20 and the interval L12 are represented in FIG. facilitates the insertion of pins 22, which are thicker and therefore more solid.
• Each complementary zone 24B comprises a complementary edge 27B, which extends facing the neighboring flared edges 27A, preferably parallel to the neighboring flared edges 27A belonging to the connection zone(s) 24A facing this complementary zone 24B.
• Each complementary edge 27B is a portion of an outer edge of the bipolar plate 12 to which this complementary zone 24B belongs.
• Each complementary edge 27B extends here parallel to the transverse direction T.
• the flared edges 27A and the complementary edges 27B are aligned with each other in the direction of stacking A1 1 .
• the flared edges 27A and the complementary edges 27B are geometrically carried by the opening plane P28.
• wedging means 30 are used to keep each flared edge 27A at a distance from the neighboring complementary edge(s) 27B, which reduces the risk of short-circuiting between two neighboring bipolar plates 12.
• one or more of the spacers 32 can be formed by a portion of a seal of the cell 14.
• one or more of the spacers 32 can be distinct from the seals but can be made of the same material as at least one of the seals of the cell.
• the spacer 32 is then preferably made during the same operation as the formation of the seal, for example during the same casting, molding or overmolding operation as the seal in question, whether this seal is integral with one of the monopolar plates 13, of the MEA 200 or whether the seal in question is a free seal.
• a stack 211 in accordance with an alternative embodiment of the invention, is represented in FIG. 6.
• the bipolar plates 12 are formed of two monopolar plates 13 welded or glued to each other in a sealed manner
• the attached seal 230 is represented schematically and not limitingly by a dotted rectangle.
• the wedging means 30 comprise three spacers 32, for example made of elastomeric material, in particular silicone, two of the spacers 32 being arranged on either side of the complementary zone 24B of this bipolar plate 12, respectively on the anode face of the bipolar plate 12 and on the cathode face of the bipolar plate 12, while the third spacer 32 is arranged between the two cathode and anode plates 13A and 13B forming this bipolar plate 12, preferably also in the complementary zone of the bipolar plate 12.
• the three spacers 32 are aligned are along the stacking axis A1 1 , so as to take up the compression forces parallel to the stacking axis A11.
• a stack 31 1 in accordance with another embodiment of the invention, is represented in FIG. 7.
• the stack 311 represented in FIG. 2 being provided in the complementary zone 24B and resting on the pockets 20 of the connection zone 24A opposite.
• Each bulge 332 forms a relief on the corresponding face of the bipolar plate 12.
• the bulges 332 form the wedging means 30.
• the associated monopolar plates 13A and 13B are here welded to each other.
• the dimensioning of the bulges 332 in the direction of the stacking direction A1 1 preferentially provides a dimensional clearance making it possible to accommodate the manufacturing and assembly tolerances of the cells 12.
• the bulges 332 are advantageously formed together with the formation of the channels 17, in particular are formed by stamping.
• the bulges 332 are made in one piece with each of the monopolar plates 13A/13B.
• the wedging means 30 are here formed in one piece with the bipolar plates 12, which is economical and quick to produce.
• a stack 411 in accordance with another embodiment of the invention, is represented in FIG. 8.
• the wedging means 30 are mounted on an edge of the bipolar plate 12 concerned, more precisely on the complementary edge 27B of the bipolar plate 12 concerned, so that the spacers 32 are located on either side of the complementary zone 24B, that is to say on each face of this bipolar plate polar 12.
• the bridge of material 434 is a flexible wall, which connects the spacers 32 to one another.
• the point of material 434 is made by a continuous wall and covers the whole of the complementary edge 27B opposite the connection zone 24A, so as to electrically insulate the complementary edge 27B from the flared flange(s) 27A opposite.
• the bridge of material 434 is preformed, so as to slightly pinch the complementary edge 27B of the bipolar plate 12 and to hold the wedging means 30 in position on the complementary zone 24B during assembly of the stack 511 .
• the wedging means 30 are glued to the bipolar plate 12.
• the complementary zone 24B comprises openings, for example holes, while the wedging members 30 comprise protrusions of a shape complementary to these openings, for example lugs complementary to the holes, the openings and the complementary protrusions cooperating together, by complementarity of shapes, so as to facilitate the positioning of the wedging members 30 when they are mounted on the corresponding complementary zone 24B.
• a stack 51 1 in accordance with another embodiment of the invention, is represented in FIG. 9.
• the spacers 32 are fixed to the membrane-electrode assembly 200 rather than to the monopolar plates 13A/13B.
• the spacers 32 are fixed to the retaining frame 206 of the MEA 200.
• each spacer 32 is positioned on a single side of the membrane-electrode assembly 200, preferably on the side oriented towards the complementary zone 24B, which makes it possible to reduce the offset, along the stacking direction A1 1 , of the peripheral portion 202 of the MEA 200 with respect to the mean plane P200, which reduces the risks of tearing of the membrane-electrode assembly 200.
• each spacer 32 rests on a flat portion of complementary zone 24B.
• the dimensioning of the spacers 32 in the direction of the stacking direction A1 1 advantageously provides a dimensional clearance making it possible to accommodate the manufacturing and assembly tolerances of the cells.
• each spacer 32 comprises two half-spacers 33, which are fixed on either side of the membrane-electrode assembly 200, in correspondence with one another in the stacking direction A11, which allows a better distribution of the forces on the membrane-electrode assembly 200 and reduces the risk of tearing the membrane-electrode assembly 200.
• the complementary zone 24B is located symmetrically opposite the connection zone 24A with respect to the center C12 of this bipolar plate 12.
• the connection zone 24A and the complementary zone 24B each have, in projection on the median plane P12, a profile.
• connection zone 24A therefore includes the flared rim 27A, which is here seen from above, and which forms an outer portion 33A of the profile of the connection zone 24A.
• connection zone 24A extends close to one of the openings 101 of the bipolar plate 12, here one of the openings 101 located at the end of one of the two rows of three openings 101, the connection zone 24A forming an internal portion 34A of the profile of the connection zone 24A.
• the profile of the complementary zone 24B includes the complementary edge 27B, which is here seen from above, and which forms an outer portion 33B of the profile of the complementary zone 24B.
• the complementary zone 24B extends close to one of the openings 101 of the other row of three openings 101, forming an internal portion 34B of the profile of the complementary zone 24B.
• the internal profile of the connection zone 24A is symmetrical, with respect to the center C12, of the internal profile of the complementary zone 24B.
• the internal profile of the connection zone 24A of a first of the two bipolar plates 12 is superimposed on the internal profile of the complementary zone 24B of the other bipolar plate 12.
• connection zone 24A is symmetrical, with respect to the center C12, of the external profile of the complementary zone 24B.
• the monopolar plates 13A and 13B are thus easy to manufacture.
• connection zones 24A and complementary 24B are arranged differently with respect to the bipolar plate 12 of Figure 11a), the connection zones 24A and complementary 24B extending close to the opening 101 in the middle of the row of three corresponding openings 101.
• each complementary zone 24B is set back from the plane of opening P28.
• the complementary zone 24B has a notch 34, so that the external profile 33B of the complementary zone 24B is set back from the external profile 33A of the connection zone 24A.
• the shape of the notch 34 is not limiting.
• each complementary edge 27B is parallel to and at a distance from the opening plane P28.
• a distance D28 is defined as being a minimum distance, parallel to the median plane P12, between this complementary edge 27B and the opposite opening plane P28.
• the distance D28 is also a distance between each complementary zone 24B and the opening plane P28, in other words a distance between each complementary zone 24B and the flared edges 27A.
• the outer profile 33B is straight, so the distance D28 is simply the distance between the complementary edge 27B and the opening plane D28. In the previous embodiments, the distance D28 is zero, or substantially zero.
• Each complementary edge 27B is thus set back from the opening plane 28, the distance D28 being greater than or equal to 1 mm, more preferably greater than or equal to 2 mm, while preferably being less than 5 mm.
• FIGS. 13 to 15 Another aspect of the invention is described with reference to FIGS. 13 to 15. We are particularly interested in the tightness, within each cell 14, between the monopolar plates 13 and the membrane-electrode assembly 200.
• the stack 11 is partially represented in FIG. 13, a monopolar plate 13, here a cathode plate 13A, and a membrane-electrode assembly 200 being visible.
• This cathode plate 13A and the membrane-electrode assembly 200 are part of a cell 14, which also includes a peripheral seal 300, also called the first seal, which is interposed between the cathode polar plate 13A and the MEA 200, in the stacking direction A11.
• the peripheral seal 300 comprises a main part 301 and fins 302.
• the peripheral seal 300 is preferably made of an elastomeric material, and impermeable to the cathode fluid used in the fuel cell 10. More generally, the peripheral seal 300 is impermeable to each of the operating fluids of the fuel cell 10.
• the stack 11 comprises a peripheral seal 300', which is interposed between this anode plate 13B and the membrane-electrode assembly 200 located opposite this anode plate 13B.
• the principles of the invention described in relation to the peripheral seals 300 associated with the cathode plates 13A can be transposed to the peripheral seals 300′ associated with the anode plates 13B.
• the peripheral seals 300 associated with the cathode plates 13A are mainly described.
• the first peripheral seal 300 is formed on the cathode pole plate 13A, for example by overmolding on the cathode pole plate 13A.
• the peripheral seal 300 is formed on the MEA 200, or even is formed separately from the cathodic pole plate 13A and from the MEA 200.
• the main part 301 is a bead of material which extends continuously and forms a closed contour, in other words a closed loop which, in the present example, extends along the peripheral zone 102, over the entire circumference of the plate 13A.
• the main part 301 surrounds the circulation field 103, the homogenization fields 104 if they are provided, and the openings 101 serving this circulation field 103.
• the main part 301 has a section in the shape of a trapezium, this shape not being limiting.
• the main part 301 comprises two longitudinal portions 301 A and 301 B, which run along the circulation field 103 and which here extend parallel to the longitudinal direction L.
• the main part 301 of the peripheral seal 300 advantageously surrounds all the openings 101 of the plate 13A.
• other seals are provided around the openings 101 which do not serve the circulation field considered.
• the main part 301 surrounds neither the connection zone 24A nor the complementary zone 24B.
• the main part 301 When the cathode plate 13A and the membrane-electrode assembly 200 are assembled within the stack 11, the main part 301 extends in a closed loop along the peripheral portion 202, here along the retaining frame 206, over the entire circumference of the peripheral portion 202.
• the main part 301 is interposed between the peripheral zone 102 and the peripheral portion 202 according to the stacking direction A 11, so as to seal off the space defined along the stacking direction A1 1 between the peripheral zone 102 of the cathode plate 13A and the peripheral portion 202 of the MEA 200, all around.
• the main part 301 also surrounds the gas diffusion layer 205, and the face of the membrane 204 facing the cathode plate 13A.
• the main part 301, the cathode pole plate 13A and the MEA 200 delimit between them a compartment 40, here a compartment cathodic.
• the main part 301 seals the cathode compartment 40 with respect to the outside of the cell 14, in particular an external zone 3 located beyond the main part 301 vis-à-vis the cathode compartment 40.
• the connection zone 24A and the complementary zone 24B are located outside the cathode compartment 40, the pockets 20 remaining accessible for their connection to the modules 18.
• Each cell 14 therefore comprises two compartments 4 0, which are respectively associated with the cathode plate 13A and the anode plate 13B delimiting this cell 14.
• the main part 301 of the first peripheral seal 300 comprises two opposite internal longitudinal surfaces 303, each arranged transversely on either side of the circulation field 103, each internal longitudinal surface 303 extending over a longitudinal portion 301 A or 301 B of the main part 301, being turned in the direction of the circulation field 103.
• Each internal longitudinal surface 303 connects the peripheral zone 102 of the plate cathode pole 13A to the peripheral portion 202 of the MEA 200 along the stacking direction A1 1 .
• Each cathode compartment 40 includes two portions called “bypass zones 50" - or by-pass in English -, which extend between the peripheral seal 300 and the circulation field 103 and which connect the openings 101 serving this circulation field 103.
• each bypass zone 50 extends between a respective longitudinal portion 301 A or 301 B and the circulation field 103.
• Each bypass zone 50 is delimited, along the stacking direction A1 1 , between the cathode pole plate 13A and the MEA 200, and is delimited, along the transverse direction T, between, on the one hand the circulation field 103 and the gas diffusion layer 205 and, on the other hand, the main part 301 of the peripheral seal 300, for a portion of this main part 301 which extends along the longitudinal direction L.
• Each bypass zone 50 extends, along the longitudinal direction L, along the circulation field 103, or even from one homogenization field 104 to another.
• the circulation field 103 extends between the two bypass zones 50 in the transverse direction T.
• the fins 302 have the function of reducing, or even preventing, a circulation of reactive fluid along the longitudinal direction L in the bypass zones 50. To do this, each fin 302 at least partially closes off a cross section of the bypass zone 50 that it occupies, the cross section being taken perpendicular to the longitudinal direction L.
• the fins 302 are distributed along the main part 301 of the joint 300, in one either, or both, cathode bypass zones 50.
• Each fin 302 is attached to one of the internal surfaces 303 of the main part 301 . In the example illustrated, the fins 302 extend projecting from each of the longitudinal portions 301 A and 301 B of the main part 301.
• Each fin 302 extends from the internal surface 303, generally in the transverse direction T, and in the direction of the circulation field 103.
• the fins 302 are formed in one piece with the main part 301.
• Each fin 302 comprises, successively and starting from the main part 301, a junction part 304, an intermediate part 305 and an end part 306.
• Each spoiler 302 is, in the illustrated examples, advantageously in the form of a low wall which presents, in the plane an extension in the median plane P12 between its junction part 304 and its extremal part 306, this extension presenting a rectilinear line profile, broken line, curve, or a profile constituted by a combination of one or more rectilinear lines and/or more or more or more or more or more or more or more or more or more or more broken lines Curves.
• the fin 302 is connected to the main part 301 via the junction part 304, which extends from the internal surface 303.
• the junction part 304 is rectilinear and its projection on the median plane P12 is perpendicular to the longitudinal direction L, that is to say parallel to the transverse direction T.
• the junction part 304 is interposed according to the stacking direction A1 1 between the peripheral zone 102 of the polar plate 13 and the peripheral portion 202 of the MEA 200.
• the intermediate part 305 of the fin 302 is attached to the junction part 304, extending it in the direction of the field 103.
• the intermediate part 305 is rectilinear and its projection on the median plane P12 is oblique with respect to the longitudinal direction L.
• the intermediate part 305 is interposed along the stacking direction A1 1 between the peripheral zone 102 and the peripheral portion 202.
• the intermediate part 305 is parallel to the longitudinal direction L, that is to say parallel to the main part 301 .
• the intermediate part 305 is inclined with respect to the transverse direction T, that is to say inclined with respect to a direction orthogonal to the longitudinal portion 301 A or 301 B to which the corresponding fin 302 is attached.
• the end part 306 of the fin 302 is attached to the intermediate part 305, extending it in the direction of the field 103.
• the end part 306 ends the fin 302.
• the end part 306 is rectilinear and its projection on the median plane P12 is perpendicular to the longitudinal direction L, that is to say is parallel to the transverse direction T.
• At least a portion of the end part 306 of the fin 302, called the contact portion 307 and including a free end of the fin 302 is interposed between the gas diffusion layer 205 and the peripheral zone 102 along the stacking direction A11.
• another portion of the end part 306, by which the end part 306 is attached to the intermediate part 305 is interposed between the peripheral zone 102 and the peripheral portion 202.
• the extremal part 306 and the intermediate part 305 form between them an angle advantageously comprised between 110° and 150°, here an angle of 120°.
• the intermediate part 305 and the junction part 304 form between them an angle advantageously comprised between 110° and 150°, here an angle of 120°.
• the contact portion 307 of the fin 302 is elastically deformed, in compression along the stacking direction A11, between the gas diffusion layer 205 and the peripheral zone 102.
• the contact portion 307 being thus compressed, it has a thickness, measured along the stacking direction A1 1 , which is less than that of the rest of the fin 302, in particular that of the junction part 304 and the intermediate part 305.
• the portion 307 initially has the same thickness along the stacking direction A1 1 as the rest of the fin 302.
• This compression deformation of the contact portion 307 can also deform the intermediate part 305. As illustrated, the intermediate part 305 takes up this deformation of the end part 30 6 twisting slightly.
• intermediate part 305 is inclined with respect to the transverse direction T prevents mechanical stresses, linked to the flattening of the contact zone 307 between the layer 205 and the peripheral zone 102, from being applied to the main part 301, which would harm the tightness of the peripheral seal 301 and/or its longevity.
• the stack 11 is generally arranged lying down, that is to say that the stacking direction A1 1 is substantially horizontal - when the vehicle is resting on a horizontal surface -, while transverse direction T of the stack is substantially vertical.
• the two longitudinal portions 301 A and 301 B are then horizontal, one of the longitudinal portions 301 A/301 B of the peripheral seal 301 being located above the other longitudinal portion 301 B/301 A of the peripheral seal 301. below the other longitudinal portion 301 B of the same peripheral seal 301.
• the water from condensation then tends to accumulate against that of the longitudinal portions 301 A or 301 B of the peripheral seal 301 which is found at the bottom.
• the cathodic plate 13a is visible, and the cathodic fluid is supposed to circulate from one of the openings 101 located on the left of Figure 13 towards one of the openings 101 located on the right of Figure 13.
• the reactive fluid circulates from the opening 101 located at the top left of the Cathode plate 13a to the opening 101 located at the bottom right.
• the reactive fluid circulates along the bypass zones 50 globally in the same direction, here to the right in the longitudinal direction L.
• the circulation of the reactive fluid along the bypass zones 50 is represented schematically by two arrows 51 A and 51 B in FIG. 15a).
• the fins 302 of the longitudinal portion 301 A of the bottom are advantageously oriented in the direction of the flow of the reactive fluid circulating along the bypass zone 50 associated with this longitudinal portion 301 A of the bottom, so as to facilitate the evacuation of the water of condensation, driven by the reactive fluid.
• the fins 302 of the longitudinal portion 301 A of the bottom are inclined in the same direction with respect to the transverse direction T, in the direction of the flow of the reactive fluid.
• the fins 302 attached to opposite longitudinal portions 301 A, 301 B are inclined in opposite directions with respect to the transverse direction T, so that even when the bipolar plates 12 are arranged head to tail, the fins 302 of the longitudinal portion 301 A or 301 B which is found at the bottom are inclined in the direction of flow of the reactive fluid .
• the fins 302 attached to the longitudinal portion 301 B of the top are inclined, with respect to the transverse axis T, in the opposite direction of the flow of the reactive fluid.
• the two opposite faces of the same bipolar plate 12 are respectively represented on the inserts a) and b) of FIG. 15, the cathode plate 13A being represented on the insert a), while the anode plate 13B is represented on the insert b).
• the same bipolar plate 12 is turned over, by rotation of 180° around the transverse axis T, which is vertical in figure 15.
• the principles of the invention defined in reference to the cathodic plate 13a of Figure 15a) are of course valid for the anodic plate 13b of Figure 15b), that is to say that the 302 fins of the longitudinal portion of the bottom - here the longitudinal portion 301 b Anodic 13b.
• the fins 302 belonging to the same longitudinal portion 301 A or 301 B are inclined in the same direction with respect to the transverse direction T.
• the direction of inclination of the fins 302 belonging to the longitudinal portion 301 A of the bottom is chosen according to the direction of flow of the reactive fluid along the corresponding bypass zone 50.
• the flows of reactive fluids are crossed on both sides of each bipolar plate 12, which means that when the polar plates 13A and 13B are seen from the front, the flows are represented in the same direction, like in FIGS. 15a) and b).
• the fins 302 belonging to opposite longitudinal portions 301 A / 301 B are inclined in opposite directions with respect to the transverse direction T.
• Peripheral seals 300 comprising fins 302' and 302' of two alternative types are respectively shown in Figures 16a) and 16b). As before, the reactant fluid is assumed to flow from left to right.
• the end part 306 is aligned with the intermediate part 305, that is to say that the assembly formed by the union of the intermediate part 305 and the end part 306 is inclined with respect to the transverse direction T.
• the fins 302 of the longitudinal portion 301 A at the bottom are inclined in the direction of the flow of the reactive fluid, while that the fins 302 attached to the longitudinal portion 301 B of the top are inclined in the opposite direction of the flow of the reactive fluid.
• the junction part 304 is aligned with the intermediate part 305, that is to say that the assembly formed by the union of the intermediate part 305 and the junction part 304 is inclined with respect to the transverse direction T.
• the fins 302 of the lower longitudinal portion 301 A are inclined in the direction of the flow of the reactive fluid, while the wings ettes 302 attached to the longitudinal portion 301 B of the top are inclined in the opposite direction of the flow of the reactive fluid.

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• 2023
  • 2023-01-23 WO PCT/EP2023/051583 patent/WO2023139265A1/fr not_active Ceased
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