Abstract:
A separator plate (10) is provided for use in a fuel cell stack, having a fuel gas flow field adjacent one surface and an oxidant gas flow field adjacent the other surface. The flowpaths of the flow fields comprise parallel flow channels (24) extending longitudinally and interconnected at their ends to form the serpentine flowpaths. The interconnections are formed by an array of spaced interconnection couplings (16, 18), that may be depressed cavities in the separator plates. The couplings for the oxidant gas flow channels are offset from those for the fuel flow channels. The interconnecting couplings may be formed by stamping, machining, or moulding the separator plate. The fuel cells in the stack are advantageously PEM-type fuel cells.
Abstract:
A flow field plate (1) has surface layers of electrically conductive material, and a core layer of electrically conductive material between the surface layers within the thickness of the plate; the plate defines multiple sets of fluid passages comprising first sets of passages (2, 3, 10), one set formed in the thickness of each surface layer and open to and parallel to the surface of that layer, a second set (4, 5, 6) of passages formed in the thickness of the core layer and extending transversely to the passages of the first sets to provide points of intersection with the latter when viewed in plan, ports (4a, 5a, 6a) placing passages of the second set in communication with passages of one or other of the first sets at points of intersection of the passages, and a third set of passages (4d, 5d, 6d) extending perpendicularly through the layers, without intersecting the first sets of passages, and each communicating with a passage or passages of the second set to provide fluid paths into, out of, or through the first sets of passages via the second set of passages.
Abstract:
The invention concerns a fluid-cooled fuel cell in which the cell surfaces are supplied with reaction media via axial supply (54, 55, 56) and radial distribution ducts (54a, 55a, 56a). The distribution ducts lie in the cell surface and extend along the cell surface edge with the open side facing the active surface. According to the invention, the supply and distribution ducts are disposed in a fuel cell stack such that distribution ducts in the edge region of the cell surfaces are stacked and staggered such that the flow of medium onto the cell surface does not occur at given points along a distribution duct but such that the entire cell surface is supplied uniformly with medium.
Abstract:
The invention concerns a PEM fuel cell comprising at least one strip membrane (17) which comprises at least two and at most 10,000 flat individual cells each consisting of an electrode layer (11, 16) applied to both sides of a membrane of a polymer solid electrolyte, the individual cells being connected in series. The fuel cell further comprises plates whic are bonded to both sides of this strip membrane (17) and have conductive regions (20) and non-conductive regions (21). The regions (20, 21) are designed such that short-circuits between the individual electrodes on one side of the membrane are avoided.
Abstract:
A method for the fabrication of an electrochemical cell which has long term chemical stability to anolyte and catholyte solutions at pH's of less than 2 and above 12, which method comprises the steps of: i) thermally processing a polymeric material which exhibits a glass transition and/or melting thermal transition to form the cell structure or components of the cell structure, and ii) subjecting the surfaces of the cell structure or components of the cell structure which, in use, will be in contact with the anolyte and catholyte solutions, to a post halogenation process, whereby the polymeric material forming the said surfaces undergoes halogen substitution to form a chemically stable halogen modified polymeric material.
Abstract:
An electrochemical fuel cell assembly includes a membrane electrode assembly which comprises an anode, a cathode having a surface thereof exposed to ambient air, and an ion exchange membrane interposed between the anode and the cathode. A seal forms a gas-impermeable barrier around the anode to which a gaseous fuel stream is supplied. The assembly further includes a thermally conductive plate having a plurality of thermally conductive members of fins extending from a major surface of the plate. The thermally conductive members contact portions of the exposed cathode surface. Adjacent thermally conductive members cooperate with the plate and the exposed cathode surface to form air conducting channels. Heat generated exothermically in the membrane electrode assembly is dissipated to the atmosphere through the thermally conductive members.
Abstract:
A method and apparatus are provided for monitoring the performance of fuel cells arranged in series. More particularly, the method and apparatus involve the measurement and comparison of fuel cell performance indicators, such as voltage, in groups of cells connected in series. In a first embodiment, the voltage across each fuel cell group is compared to a reference voltage equal to a predetermined minimum voltage. In a second embodiment, the voltage across each group is compared to a reference voltage equal to the average across all fuel cell groups. In a third embodiment, a reference voltage equal to the voltage across one group is compared to the voltage across each of the other fuel cell groups. In a fourth embodiment, the voltage across each group is compared as a reference voltage to the voltage across an adjacent fuel cell group. Other embodiments comprising various combinations of the first, second, third and fourth embodiments are also provided. An alarm is activated, and supply of fuel to the cells discontinued, when the measured voltage for a fuel cell group varies from the reference voltage by more than a predetermined voltage differential.
Abstract:
Die Erfindung betrifft ein Brennstoffzellensystem mit einem Brennstoffzellenstapel (1), gebildet aus einer Mehrzahl von Gasdiffusionsschichten aufweisenden Zelleinheiten (2, 4), wobei die Gasdiffusionsschicht mindestens einer der randseitigen Zelleinheiten (2) gegenüber der Gasdiffusionsschicht einer Zelleinheit (4) aus der Mitte des Brennstoffzellenstapels (1) einen Wärmetransportmechanismus verminderter Effizienz aufweist. Die Erfindung betrifft weiterhin ein Kraftfahrzeug mit einem verbesserten Brennstoffzellensystem.