Abstract: A gas-diffusing device, including a superposition of a layer of composite material including electrically conductive fibres and a polymerized resin coating said conductive fibres; a first electrically conductive layer having an open porosity between first and second faces and including a first void in the second face, the first face making electrical contact with the conductive fibres of the layer of composite material, the polymerized resin coating one portion of the first conductive layer on the first face.

Abstract: A method for welding between two metallic plates, including: (a) fitting a solid plate without openings, configured to be transparent at at least one emission wavelength of a laser beam (F) emitted by a laser (L), between the laser (L) and at least one contact zone between the metallic plates to be welded; (a1) inerting of the contact zone via a netural gas, where the neutral gas circulates in channels delimited by the contact zone between the metallic plates and by the solid plate; (a2) exerting pressure on the two metallic plates to apply them against one another in the contact zone to be welded, where the application pressure is exerted by the solid plate directly in contact with one of the two metallic plates to be welded; and (b) emission of a laser beam, through the solid plate, to perform welding of the metallic plates in the contact zone.

Abstract: A process for manufacturing a gas diffusion device includes providing a superposition of a composite layer and of an electrically conductive element, the composite layer including electrically conductive fibers and a polymerizable resin impregnating the conductive fibers, and the electrically conductive element having an open porosity between a first face and a second face. The process also includes compressing the superposition of the composite layer and of the conductive element so as to bring said conductive fibers into contact with the first face of the element, so as to make said resin flow into said element without the resin impregnating all the volume of said conductive element; and polymerizing the resin.

Abstract: The invention relates to a method for determining the dimensions of an electrochemical cell allowing a total area of the electrochemical cell to be minimized while maximizing an electrical signal generated by the electrochemical cell in operation, including: a/ determining a first cost function expressing the variation in a first parameter representative of the total area as a function of an adjustment variable representative of an aspect ratio of the active zone; b/ determining a second cost function expressing the variation in a second parameter representative of the generated electrical signal as a function of the adjustment variable; c/ determining a compound cost function from the first and second cost functions and identifying a value of the adjustment variable that optimizes the compound cost function and that therefore conjointly optimizes the first and second cost functions.

Abstract: A gas-diffusing device, including a superposition of a layer of composite material including electrically conductive fibres and a polymerized resin coating said conductive fibres; a first electrically conductive layer having an open porosity between first and second faces and including a first void in the second face, the first face making electrical contact with the conductive fibres of the layer of composite material, the polymerized resin coating one portion of the first conductive layer on the first face.

Abstract: The invention relates to a method for determining the dimensions of an electrochemical cell allowing a total area of the electrochemical cell to be minimized while maximizing an electrical signal generated by the electrochemical cell in operation, including: a/ determining a first cost function expressing the variation in a first parameter representative of the total area as a function of an adjustment variable representative of an aspect ratio of the active zone; b/ determining a second cost function expressing the variation in a second parameter representative of the generated electrical signal as a function of the adjustment variable; c/ determining a compound cost function from the first and second cost functions and identifying a value of the adjustment variable that optimizes the compound cost function and that therefore conjointly optimizes the first and second cost functions.

Abstract: The invention relates to a method for welding between two metallic materials (2, 3) or for sintering of powder(s) (P), comprising the following steps: a/ fitting a solid plate (10), transparent at the emission wavelength(s) of a laser beam (F), between said laser (L) and at least one contact zone (4) between the metallic materials to be welded or at least one sintering zone of the powder(s); b/ emission of the laser beam, through the transparent plate, to perform welding of the materials in the contact zone(s) or sintering of powder(s) in the sintering zone(s).

Abstract: A method for evaluating sealing of a bipolar structure including a sheet-like substrate forming a current collector, and two electrodes in a form of films arranged on opposite surfaces of the substrate, respectively, the method including: placing the bipolar structure in a cavity to define first and second compartments therein, which are separated by the bipolar structure, a periphery of which is sealingly connected to the cavity; circulating a fluid in the first compartment of the cavity toward the second compartment; and evaluating sealing of the bipolar structure from a measurement of difference in pressure of the fluid in the first and second compartments.

Abstract: A cell structure for a fuel-cell battery, which allows the compromise necessary between the reduction in the non-uniformities of mechanical stress to be optimized, with the aim of obtaining a more uniform operation, and the independent accommodation with respect to the defects in planarity/thickness/alignment, while at the same time meeting the compactness constraint, comprises: a membrane/electrode assembly comprising a first electrode and a second electrode separated by a membrane; a gas diffusion layer stacked on each face of the assembly, between an electrode of the assembly and a current collector plate; and the gas diffusion layers stacked on either side of the assembly do not have the same rigidity, one of the gas diffusion layers having a Young's modulus relative to an applied stress in the direction of the thickness, greater than the Young's modulus of the other layer, in a ratio of the order of at least 100.

Abstract: A method for measuring the thermal conductivity along three directions of an anisotropic thin material includes: positioning on the surface of the material a plurality N of sensors able to measure the temperature of the material at N measuring points; generating a heat flux from a heat source positioned on a surface of the material; determining a mapping of the theoretical temperature of the material at the N measuring points of the N sensors along three directions by using a calculator, determining a mapping of the real temperature on the surface of the anisotropic material by measuring the temperature of the material at the N measuring points of N sensors; determining using the calculator the real thermal conductivity of the thin anisotropic material, along three directions, by a plurality of adjustments of the theoretical thermal conductivity by minimising the difference between the theoretical temperature and the real temperature for each of the N temperature measuring points.

Abstract: This gas diffusion layer for a PEMFC includes at least one hydrophilic electronically-conductive thread, advantageously formed of a carbon thread, of an electronically conductive hydrophilic material thread, or of a polymer thread loaded with electronically-conductive particles.