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: 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: 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: 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: 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: 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 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 with 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 on 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: A fluid impermeable thin film is fabricated on a porous substrate by depositing a material having a certain spatial oxidation expansion. After deposition, the material is oxidized whereby the deposited material expands and forms a void free film on top of the porous substrate. The snuggly contacting grain boundaries of the void free film may recombine to a continuous thin film that has a thickness of only a fraction of 1 ?m and is substantially fluid impermeable. The small film height contributes to a high ionic conductivity that makes the thin film a preferred choice for a fuel cell electrolyte membrane enabling efficient fuel cell operation at temperatures well below 500° C.

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 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 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: 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 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: A fluid impermeable thin film is fabricated on a porous substrate by depositing a material having a certain spatial oxidation expansion. After deposition, the material is oxidized whereby the deposited material expands and forms a void free film on top of the porous substrate. The snuggly contacting grain boundaries of the void free film may recombine to a continuous thin film that has a thickness of only a fraction of 1 &mgr;m and is substantially fluid impermeable. The small film height contributes to a high ionic conductivity that makes the thin film a preferred choice for a fuel cell electrolyte membrane enabling efficient fuel cell operation at temperatures well below 500° C.

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.