Abstract:
An electrically conductive flow-field plate in a proton exchange membrane fuel cell comprises a composition made of a resin and a plurality of carbon nanotubular fibers having an average diameter is at least about 0.5 nm and up to about 300 nm. The carbon nanotubular fibers are present at not more than about 85 wt.%. The resin can be of a thermoplastic type, a fluorinated type, a thermosetting type and a liquid crystalline type.
Abstract:
An electrochemical fuel cell contains first and second monolithic electrically conducting flow field-bipolar plate assemblies arranged essentially parallel to each other such that an inside surface of the first bipolar separator plate is facing an inside surface of the second bipolar separator plate, wherein the bipolar separator plates (9) are electrically and mechanically connected by intervening layers (8, 5, 6, 7) that are directly bonded to each other. The fuel cells can be stacked between endpaltes and supplied with hydrogen and oxygen to generate electric power. An air cooled condenser for use with a fuel cell stack is composed of a porous foam condensing element and a porous foam cooling element. The condenser can be placed by a fuel cell stack for cooling purposes.
Abstract:
In a PEM-type fuel cell, coolant conduits (79) are provided that follow the reactant gas flowpaths on either side of the MEA (70) and are formed in the interface between adjacent contacting separator layers (72) of consecutive fuel cells in the stack. These coolant conduits can eliminate the need for coolant conduits that pass in the stack dimension through the MEA layers.
Abstract:
An improved molding process provides highly conductive polymer composite parts having bulk conductivity over 10 S/cm. This conductivity is particularly useful in collector plate for use in fuel cells. The process can include compounding of a mixture of conductive filler with a polymer binder, extruding the mixture after the binder is plasticized to make pellets. The pellets can then be introduced to a dual temperature feed container of an injection molding machine and injected under high pressure and velocity into the mold cavity. The resulting parts, and particularly collector plates can be made economically and provide a high conductivity while maintaining strength and chemical resistance properties.
Abstract:
A bipolar separator plate for fuel cells consists of a molded mixture of a vinyl ester resin and graphite powder. The plate serves as a current collector and may contain fluid flow fields for the distribution of reactant gases. The material is inexpensive, electrically conductive, lightweight, strong, corrosion resistant, easily mass produced, and relatively impermeable to hydrogen gas. The addition of certain fiber reinforcements and other additives can improve the properties of the composite material without significantly increasing its overall cost.
Abstract:
A unit cell comprises a pair of electrodes, each having a catalytic layer and a gas diffusion layer; an electrolyte layer placed between the electrodes; a separator provided outside one electrode and including a passage for delivering fuel gas to the electrode; and a separator provided outside the other electrode and including a passage for delivering oxidant gas to the electrode. Such unit cells are stacked to form a fuel cell. At least any of the catalytic layer, the gas diffusion layer and the surface of the passage have repellency. This fuel cell exhibits desirable characteristics.
Abstract:
A unit cell is composed of a pair of electrodes with a catalyst layer, a polymer electrolyte film interposed between the pair of electrodes, a separator having means for supplying hydrogen-containing gas to one of the electrodes, and a separator having means for supplying oxidizing gas to the other electrodes. A plurality of such cells are stacked with sealant applied to at least part of the peripheries of the electrodes so as to form a polymer electrolyte fuel cell. This polymer electrolyte fuel cell is superior in durability and productivity. For high reliability, a gasket sealant, the sealant for cooling water, and the sealant for water or the gas in an internal humidifier can be formed of a polymer compound having a main chain skeleton of polyisobutylene.
Abstract:
New fuel cell components for use in liquid feed fuel cell systems are provided. The components include biplates (70) and endplates (40), and allow high efficiency operation. Conductive elements (44) and a wicking device (60) also form a part of the fuel cell components of the invention.
Abstract:
The present invention provides a separator for electrochemical cells, comprising a gas barrier having an electrically conducting pathway extending therethrough and a porous, electrically conducting member in electrical contact with each side of the electrically conducting pathway. In another aspect of the invention, a separator for electrochemical cells is provided comprising a porous, electrically conducting sheet and a gas impermeable material disposed within a portion of the sheet to form a gas barrier. In yet another aspect of the invention, a separator for electrochemical cells is provided comprising two porous, electrically conducting sheets and an electrically conducting gas barrier disposed in electrical contact between the sheets.
Abstract:
Improved fuel cell stacks (1) constructed from a plurality of cells, each comprising a series of interrelated mono and bipolar collector plates (BSPs), which in turn are built up by lamination of a core of related non-conductive plastic or ceramic platelets (12) sandwiched between conductive microscreen platelets of metal or conductive ceramic or plastic with an electrode membrane (EMA) (5 A, B, C, D) between adjacent BSPs. The platelets, both metal and plastic of the composite BSPs, are produced from sheet material with through and depth features (18, 17) formed by etching, pressing, stamping, casting, embossing and the like. Adjacent plates each with correspondingly relieved features form serpentine channels within the resultant monolithic platelet/cell stack for integrated fluid and thermal management. The plastic platelets are particularly useful for PEM fuel cells employing H2 and Air/O2 as fuel. The platelets are easily made by printing (embossing) processes, and dies made by photolithographic etching for rapid redesign. Each BSP can be individually tailored to each type of membrane, fuel, and intra-cell location within the stack (1). As materials are cheap and easy to manufacture and assemble, lightweight fuel cells of very high power density are realizable. Industrial applicability includes both stationary and vehicular power supplies, in both micro and macro sizes.