Abstract: In a fuel cell assembly typically comprising a plurality of cells each comprising an electrolyte layer (2), a pair of gas diffusion electrode layers (3, 4), and a pair of flow distribution plates (5), each flow distribution plate is provided with a central recess (51, 52) having a number of projections (53, 54) formed therein; and an electrode terminal layer (55, 56) is formed on each projection to establish a connection with an external circuit; each gas diffusion electrode layer defining the passages for fuel and oxidizer gases by covering the central recess, and provided with a porous layer (3a, 4a) typically in the form of a nano-tube carbon film, formed over each flow distribution plate. Because the porous layer is directly formed on each flow distribution plate, the thickness of each gas diffusion electrode layer can be freely controlled, and the overall thickness of the assembly can be minimized so as to allow a compact design.

Abstract: In a fuel cell assembly typically with a plurality of cells each including an electrolyte layer (2), a pair of gas diffusion electrode layers (3, 4), and a pair of flow distribution plates (5), the electrolyte layer (2) comprises a frame (21) and electrolyte (22) retained in the frame; and the flow distribution plates and frames are made of materials having similar thermal expansion properties so that the generation of thermal stress between the frames of the electrolyte layers and the corresponding flow distribution plates can be avoided, and the durability of the various components can be ensured. By joining each flow distribution plate with the corresponding frame by anodic bonding or using a bonding agent along a periphery thereof, the need for a sealing arrangement such as a gasket or a clamping arrangement can be eliminated, and this contributes to the compact design of the assembly.

Abstract: A method for forming a carbon nanotube (5) on an electroconductive member (2). A catalytic layer (3) including a metal or alloy that serves as a catalyst for growing the carbon nanotube is formed on an electroconductive member, the metal or alloy of the catalytic layer is processed so as to turn it into small particles (3a) by heating the catalytic layer formed on the electroconductive member to a prescribed temperature while supplying inert gas, and a carbon nanotube is grown on the electroconductive member by using the small particles of the metal or alloy of the catalytic layer as a catalyst. The fine metallic particles that can be used as a catalyst for growing the carbon nanotube can be prepared in a simple, economical and efficient manner. The carbon nanotube is highly suitable for use as the diffusion layer of a fuel cell.

Abstract: A fuel cell assembly is provided that includes a plurality of cells. Each cell includes an electrolyte layer (2), a pair of gas diffusion electrode layers (3, 4) interposing the electrolyte layer between them, and a pair of flow distribution plates (5) for defining passages (10, 11) for fuel and oxidizer gases that contact the gas diffusion electrode layers. The electrolyte layer (2) includes a frame (21) with a grid (21a), which has a number of through holes (21b), and electrolyte (22) retained in each of the through holes. Because the electrolyte is not required to be interposed between structural members such as the gas diffusion electrode layers and flow distribution plates, the electrolyte is allowed to expand into the passages for the fuel and oxidizer gases so that no undesirable stresses are produced, and the structural members would not be affected by the expansion of the electrolyte.

Abstract: Water flooding at the cathode of a fuel cell is a common problem in fuel cells. By integrating an electroosmotic (EO) pump to remove product water from the cathode area, fuel cell power can be increased. Integration of EO pumps transforms the designs of air channel and air breathing cathodes, reducing air pumping power loads and increasing oxidant transport. Hydration of gas streams, management of liquid reactants, and oxidant delivery can also be accomplished with integrated electroosmotic pumps. Electroosmotic pumps have no moving parts, can be integrated as a layer of the fuel cell, and scale with centimeter to micron scale fuel cells.

Abstract: In a fuel cell assembly comprising a plurality of cell each including an electrolyte layer (2), a pair of diffusion electrode layers (3, 4) interposing the electrolyte layer between them, and a pair of flow distribution plates (5) for defining passages (11) for fuel and oxidant fluids that contact the diffusion electrode layers, the fuel cells are arranged on a common plane. Therefore, the vertical dimension of the fuel cell assembly can be minimized, and a fuel cell assembly of favorable electric properties can be achieved. Each flow distribution plate is typically formed with communication passages for communicating fluid passages defined on each side of the electrolyte layer at a prescribed pattern. The communication passages and through holes communicate the fluid passages in such a manner that adjacent fuels cells have opposite polarities.

Abstract: A bistable minivalve includes a movable component, an actuator that is electrostatically, magnetically, or mechanically coupled to the movable component for controllably switching the movable component between open and closed states, and a casing providing structural support. The movable component has an actuation surface [300] movably positioned in the valve conduit and a bistable element attached to the actuation surface providing mechanical stability to the open and closed states of the movable component. The bistable element may be realized as a pair of elastic buckling beams [302, 304] attached at their midpoints to opposite sides of the actuation surface. Optionally, there may also be elastic support beams [306, 308] attached at their endpoints to the actuation surface and attached at their midpoints to the elastic buckling beams.

Abstract: In a fuel cell assembly (1) comprising a pair of separators (11, 12) each for defining a recess (10) serving as a conduit for a fuel fluid or an oxidizer fluid, a feedthrough conductive path for connecting top and under surfaces of each separator is achieved by a second electroconductive film (36) formed on a side wall of a through-hole (33) extending through each separator (11, 12) in such a manner that the second electroconductive film (36) connects a first electroconductive film (35) constituting a top surface of a projection (30) provided in the recess (10) to a third electroconductive film (37) formed on a surface opposite to that formed with the recess (10).

Abstract: In a fuel cell assembly (1) comprising an electrolyte layer (2) having a frame (21) and an electrolyte (22) retained in the frame, a pair of separators (5, 6) are bonded to the electrolyte layer by that a metallic material (27) is deposited on one of the frame and each separator and a laser beam is irradiated onto the metallic material through the frame or the separator in a state that the frame and each separator contact each other whereby the metallic material forms a eutectic with the other of the frame and each separator.

Abstract: In a fuel cell assembly (100, 200), a diffusion layer (113, 114, 201) comprises an electroconductive film (133, 133a, 133b) formed integrally with a separator (115, 116, 115a) so as to form a unitary separator-diffusion layer assembly (130, 131, 130a, 203). The electroconductive film of the diffusion layer can be formed on the separator by a process comprising physical vapor deposition, chemical vapor deposition, spin coating, sputtering or screen printing.

Abstract: A fuel cell contains an electrolyte sheet sandwiched between two electrodes. One or both electrode/electrolyte interfaces includes mesoscopic three-dimensional features in a prescribed pattern. The features increase the surface area-to-volume ratio of the device and can be used as integral channels for directing the flow of reactant gases to the reaction surface area, eliminating the need for channels in sealing plates surrounding the electrodes. The electrolyte can be made by micromachining techniques that allow very precise feature definition. Both selective removal and mold-filling techniques can be used. The fuel cell provides significantly enhanced volumetric power density when compared with conventional fuel cells.

Abstract: A fuel cell assembly is provided with at least one cell including an electrolyte layer, a pair of gas diffusion electrode layers interposing the electrolyte layer between them, and a pair of flow distribution plates for defining passages for fuel and oxidizer gases that contact the gas diffusion electrode layers. The electrolyte layer includes a grid frame provided with a plurality of through holes, and electrolyte retained in each through hole, heater wire being disposed in a grid bar of the grid frame so that the entire catalyst and electrolyte may be heated up to a desired temperature suitable for the reaction, instead of being heated only locally, in a short period of time, and the desired output can be obtained in a short period of time following the start-up.

Abstract: A simple, inexpensive and highly efficient fuel cell has boundary structures made of a photo-sensitive material in combination with selective patterning. Printed circuit board (PCB) fabrication techniques combine boundary structures with two and three dimensional electrical flow path. Photo-sensitive material and PCB fabrication techniques are alternately or combined utilized for making micro-channel structures or micro stitch structures for substantially reducing dead zones of the diffusion layer while keeping fluid flow resistance to a minimum. The fuel cell assembly is free of mechanical clamping elements. Adhesives that may be conductively contaminated and/or fiber-reinforced provide mechanical and eventual electrical connections, and sealing within the assembly. Mechanically supporting backing layers are pre-fabricated with a natural bend defined in combination with the backing layers' elasticity to eliminate massive support plates and assist the adhesive bonding.

Abstract: In a fuel cell assembly comprising a plurality of cell each including an electrolyte layer (2), a pair of diffusion electrode layers (3, 4) interposing the electrolyte layer between them, and a pair of flow distribution plates (5) for defining passages (10, 11) for fuel and oxidant fluids that contact the diffusion electrode layers, the fuel cells are arranged on a common plane. Therefore, the vertical dimension of the fuel cell assembly can be minimized, and a fuel cell assembly of favorable electric properties can be achieved. Each flow distribution plate is typically formed with communication passages for communicating fluid passages defined on each side of the electrolyte layer at a prescribed pattern. The communication passages and through holes communicate the fluid passages in such a manner that adjacent fuels cells have opposite polarities.

Abstract: In a fuel cell assembly comprising at least one cell including an electrolyte layer, a pair of gas diffusion electrode layers interposing said electrolyte layer between them, and a pair of flow distribution plates (5) for defining passages (10, 11) for fuel and oxidizer gases that contact said gas diffusion electrode layers, a heater (62) and various sensors (61a, 61b and 61c) are formed at least one of the flow distribution plates so that the work needed for installing the heater and sensors is simplified. By embedding them in a substrate, the need for a complex sealing arrangement can be eliminated. In particular, if each flow distribution plate is formed by performing an etching process on a substrate, and forming the heater and sensors in succession to the step of forming each flow distribution plate, the installation of sensors and fabrication of the fuel call are simplified.

Abstract: In a fuel cell comprising a tubular casing, an electrolyte layer received in the tubular casing, and a pair of gas diffusion electrodes interposing the electrolyte layer and defining a fuel gas passage and an oxidizing gas passage, respectively, each gas diffusion electrode is formed by stacking a plurality of layers of material therefor, for instance in the axial direction of the casing. Because the gas diffusion layers are formed layer by layer, components can be formed in highly fine patterns so that a highly compact tubular fuel cell can be achieved. Similarly, the dimensions of the various elements of the fuel cell can be controlled in a highly accurate manner. Also, the geometric arrangement can be changed at will in intermediate parts of each gas passage.

Abstract: In a fuel cell assembly typically consisting of a plurality of cells each comprising an electrolyte layer (2), a pair of gas diffusion electrode layers (3, 4), and a pair of flow distribution plates (5), the electrolyte layer (2) comprises a frame (21) and electrolyte (22) retained in the frame; and the flow distribution plates and frames are made of materials having similar thermal expansion properties so that the generation of thermal stress between the frames of electrolyte layers and the corresponding flow distribution plates can be avoided, and the durability of the various components can be ensured. By joining each flow distribution plate with the corresponding frame by anodic bonding or using a bonding agent along a periphery thereof, the need for a sealing arrangement such as a gasket or a clamping arrangement can be eliminated, and this contributes to the compact design of the assembly.

Abstract: In a fuel cell assembly typically consisting of a plurality of cells each comprising an electrolyte layer (2), a pair of gas diffusion electrode layers (3, 4) interposing the electrolyte layer between them, and a pair of flow distribution plates (5) for defining passages (10, 11) for fuel and oxidizer gases that contact the gas diffusion electrode layers, the electrolyte layer (2) comprises a frame (21) including a grid (21a) having a number of through holes (21b), and electrolyte (22) retained in each of the through holes. Because the electrolyte is not required to be interposed between structural members such as the gas diffusion electrode layers and flow distribution plates, the electrolyte is allowed to expand into the passages for the fuel and oxidizer gases to that no undesirable stresses are produced, and the structural members would not be affected by the expansion of the electrolyte.

Abstract: A fuel cell assembly is provided with at least one cell including an electrolyte layer, a pair of gas diffusion electrode layers interposing the electrolyte layer between them, and a pair of flow distribution plates for defining passages for fuel and oxidizer gases that contact the gas diffusion electrode layers. The electrolyte layer includes a grid frame provided with a plurality of through holes, and electrolyte retained in each through hole, heater wire being disposed in a grid bar of the grid frame so that the entire catalyst and electrolyte may be heated up to a desired temperature suitable for the reaction, instead of being heated only locally, in a short period of time, and the desired output can be obtained in a short period of time following the start-up.

Abstract: In a fuel cell comprising a tubular casing, an electrolyte layer received in the tubular casing, and a pair of gas diffusion electrodes interposing the electrolyte layer and defining a fuel gas passage and an oxidizing gas passage, respectively, each gas diffusion electrode is formed by stacking a plurality of layers of material therefor, for instance in the axial direction of the casing. Because the gas diffusion layers are formed layer by layer, components can be formed in highly fine patterns so that a highly compact tubular fuel cell can be achieved. Similarly, the dimensions of the various elements of the fuel cell can be controlled in a highly accurate manner. Also, the geometric arrangement can be changed at will in intermediate parts of each gas passage.