A fuel cell stack including a plurality of fuel cell units having a truncated cone shape and connected in series with each other is proposed. The series connection of the fuel cell units may be made such that a relatively small outer diameter portion of one of the fuel cell units is inserted into a relatively large outer diameter portion of another fuel cell unit adjacent to the one fuel cell unit.

Porous solid materials are provided. The porous solid materials include a plurality of interconnected wires forming an ordered network. The porous solid materials may have a predetermined volumetric surface area ranging between 2 m.sup.2/cm.sup.3 and 90 m.sup.2/cm.sup.3, a predetermined porosity ranging between 3% and 90% and an electrical conductivity higher than 100 S/cm. The porous solid materials may have a predetermined volumetric surface area ranging between 3 m.sup.2/cm.sup.3 and 72 m.sup.2/cm.sup.3, a predetermined porosity ranging between 80% and 95% and an electrical conductivity higher than 100 S/cm. The porous solid materials (100) may have a predetermined volumetric surface area ranging between 3 m.sup.2/cm.sup.3 and 85 m.sup.2/cm.sup.3, a predetermined porosity ranging between 65% and 90% and an electrical conductivity higher than 2000 S/cm. Methods for the fabrication of such porous solid materials and devices including such porous solid material are also disclosed.

Porous solid materials are provided. The porous solid materials include a plurality of interconnected wires forming an ordered network. The porous solid materials may have a predetermined volumetric surface area ranging between 2 m.sup.2/cm.sup.3 and 90 m.sup.2/cm.sup.3, a predetermined porosity ranging between 3% and 90% and an electrical conductivity higher than 100 S/cm. The porous solid materials may have a predetermined volumetric surface area ranging between 3 m.sup.2/cm.sup.3 and 72 m.sup.2/cm.sup.3, a predetermined porosity ranging between 80% and 95% and an electrical conductivity higher than 100 S/cm. The porous solid materials (100) may have a predetermined volumetric surface area ranging between 3 m.sup.2/cm.sup.3 and 85 m.sup.2/cm.sup.3, a predetermined porosity ranging between 65% and 90% and an electrical conductivity higher than 2000 S/cm. Methods for the fabrication of such porous solid materials and devices including such porous solid material are also disclosed.

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.

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.

Aspects of the subject disclosure may include, for example, a porous electrode that includes a porous layer, and a pattern of flow channels defined in the porous layer, wherein a first flow channel in the pattern of flow channels has a shape that at least partially approximates a cube-root profile. Additional embodiments are disclosed.

A electrochemical cell device includes: a cell having a first main surface and a second main surface opposite to the first main surface; a first current collector having a third main surface facing the first main surface; and a second current collector having a fourth main surface facing the second main surface. The cell is warped to protrude from the second main surface toward the first main surface. The third main surface is provided with a recess at a position facing a central portion of the first main surface. The fourth main surface includes a protrusion at a position facing a central portion of the second main surface. Each of the first current collector and the second current collector is constituted of one or more metal porous body sheets each composed of a metal porous body having a framework with a three-dimensional network structure.

At least one embodiment relates to a method for transforming at least part of a valve metal layer into a template that includes a plurality of spaced channels aligned longitudinally along a first direction. The method includes a first anodization step that includes anodizing the valve metal layer in a thickness direction to form a porous layer that includes a plurality of channels. Each channel has channel walls and a channel bottom. The channel bottom is coated with a first insulating metal oxide barrier layer as a result of the first anodization step. The method also includes a protective treatment. Further, the method includes a second anodization step after the protective treatment. The second anodization step substantially removes the first insulating metal oxide barrier layer, induces anodization, and creates a second insulating metal oxide barrier layer. In addition, the method includes an etching step.

At least one embodiment relates to a method for transforming at least part of a valve metal layer into a template that includes a plurality of spaced channels aligned longitudinally along a first direction. The method includes a first anodization step that includes anodizing the valve metal layer in a thickness direction to form a porous layer that includes a plurality of channels. Each channel has channel walls and a channel bottom. The channel bottom is coated with a first insulating metal oxide barrier layer as a result of the first anodization step. The method also includes a protective treatment. Further, the method includes a second anodization step after the protective treatment. The second anodization step substantially removes the first insulating metal oxide barrier layer, induces anodization, and creates a second insulating metal oxide barrier layer. In addition, the method includes an etching step.

A bipolar flat element comprising a coating that contains expanded graphite and a binder, the coating being applied to at least one of the two primary surfaces of a flat, electrically conductive element.