A bipolar plate for a PEM hydrogen fuel cell is coated with a carbon-containing coating, the carbon-containing coating comprising in order: a) a titanium seed layer; b) a titanium nitride interfacial layer; and c) a a-C top layer, and wherein the bipolar plate is formed from stainless steel. Methods for making such coated plates are described. The a-C has a density of greater than 2.0 g/cm3, a molar hydrogen content of 5% or less, an sp2 carbon content of 40% to 80% and an sp3 carbon content of 20% to 60%. The coated plates possess good electrical conductivity and are resistant to corrosion.

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.

A method of producing a flow field plate for a fuel cell comprises over-profiling relief features in a die set to more accurately reproduce the intended flow channel features in the pressed plate. The process includes determining a target relief profile of features extending across the plate along at least a first dimension of the plate, modulating the relief profile with an over-profiling parameter, as a function of the first dimension; forming a die with the modulated relief profile; and pressing a flow field plate using the die with modulated relief profile to thereby produce the unmodulated, target relief profile in the flow field plate.

A fluid flow plate for an electrochemical fuel cell assembly comprises a first plurality of fluid flow channels extending across an area of the flow plate to define a flow field of the fluid flow plate. An array of first fluid transfer points is disposed along an edge of the flow field for communicating fluid into or out of the fluid flow channels. A gallery has a first peripheral edge portion bounded by the array of first fluid transfer points and at least two second peripheral edge portions each bounded by an array of second fluid transfer points disposed along fluid access edges of the fluid flow plate. The at least two second peripheral edge portions are disposed at oblique angles to the first peripheral edge portion such that the total length of the any of second fluid transfer points is at least as long as, and preferably longer than, the length of the array of first fluid transfer points. Disposing the at least two second peripheral edge portions at oblique angles to the first peripheral edge portion enables the lengths of the second peripheral edge portions of each gallery to be increased compared to the length of the first fluid transfer points (i.e. width of the active flow field area) which optimizes fluid distribution into the channels of the flow plate.

A fluid flow plate for an electrochemical fuel cell assembly comprises a first plurality of fluid flow channels extending across an area of the flow plate to define a flow field of the fluid flow plate. An array of first fluid transfer points is disposed along an edge of the flow field for communicating fluid into or out of the fluid flow channels. A gallery has a first peripheral edge portion bounded by the array of first fluid transfer points and at least two second peripheral edge portions each bounded by an array of second fluid transfer points disposed along fluid access edges of the fluid flow plate. The at least two second peripheral edge portions are disposed at oblique angles to the first peripheral edge portion such that the total length of the any of second fluid transfer points is at least as long as, and preferably longer than, the length of the array of first fluid transfer points. Disposing the at least two second peripheral edge portions at oblique angles to the first peripheral edge portion enables the lengths of the second peripheral edge portions of each gallery to be increased compared to the length of the first fluid transfer points (i.e. width of the active flow field area) which optimizes fluid distribution into the channels of the flow plate.

Methods and systems are provided for manufacturing a bipolar plate for a redox flow battery. In one example, the bipolar plate is fabricated by a roll-to-roll process. The bipolar plate includes a non-conductive substrate that is coupled to a negative electrode on a first surface and coupled to a positive electrode on a second surface, the first surface opposite of the second surface.

In order to provide a bipolar plate for a fuel cell, providing an anode plate with an anode side and a coolant side, wherein a first structuring for forming an anode flow field is formed on the anode side, and a cathode plate with a cathode side and a coolant side, wherein a second structuring for forming a cathode flow field is formed on the cathode side; wherein structural elements, which are contacted by the coolant sides of the anode plate and the cathode plate, for forming a coolant flow field, are arranged between the anode plate and the cathode plate, which bipolar plate has an optimized pressure distribution in a fuel cell stack and increased stability in comparison with the prior art, it is proposed that the structural elements may be made of an elastic material and that the structural elements have a different height in different regions of the coolant flow field. A fuel cell stack and a vehicle are also disclosed.

A bipolar plate for an electrolyzer, particularly a PEM electrolyzer, is formed with a central region and a peripheral region surrounding the central region. With a view to cost-effective production of the bipolar plate, the central region is made of metal sheet and the peripheral region is formed from a plastic frame. The plastic frame is made of at least one thermoplastic, particularly at least one high-temperature thermoplastic, and is injection-molded around the sheet metal.

A bipolar plate for an electrolyzer, particularly a PEM electrolyzer, is formed with a central region and a peripheral region surrounding the central region. With a view to cost-effective production of the bipolar plate, the central region is made of metal sheet and the peripheral region is formed from a plastic frame. The plastic frame is made of at least one thermoplastic, particularly at least one high-temperature thermoplastic, and is injection-molded around the sheet metal.

A fuel cell system with reduced leakage and a method of assembling a fuel cell system. Bipolar plates within the system include reactant channels and coolant channels that are fluidly coupled to inlet and outlet flowpaths, all of which are formed within a coolant-engaging or reactant-engaging surface of the plate. One or more seals are also formed on the fluid-engaging surface to help reduce leakage by maintaining fluid isolation of the reactants and coolant as they flow through their respective channels and flowpaths that are defined between adjacently-placed plates. The seal—with its combination of in-plane and out-of-plane dimensions—forms a substantially hollow volume, into which a plug is placed to reduce the tendency of the seal to form a shunted flow of the coolant or reactant around the intended active area of the plate. A fluid port intersection is integrally formed with the seal and is formed to be fluidly cooperative with the volume, and is capable of accepting the introduction of a fluent precursor of the plug material such that upon curing, the precursor material forms a substantially rigid insert that continuously fills both the volume and intersection, thereby increasing the resistance of the plug to movement and the seal to shunted flow. In one form, the geometry of the fluent material injection site is such that it promotes plug anchoring within its intended location, while also providing a manufacturing aid to visually inspect for plug installation, as well as to serve as a bipolar plate stacking alignment locator and verification.