Abstract: A fuel cell stack structure includes, for example, a plurality of unit cells each having an aperture formed therethrough. A first fuel cell stack is formed by stacking the plurality of unit cells in a stacking direction and has an internal manifold opening defined by the apertures. A fluid passage within the cell for flowing a fluid that flows within the internal manifold is configured and arranged to flow the fluid in a direction generally perpendicular to the stacking direction of the unit cell. The structure also includes an external manifold having an external passage for supplying the fluid to the internal manifold, wherein an external manifold surface facing a flow direction of the fluid creates a vortex in fluid flowing within the external passage proximal to the internal manifold.

Abstract: Provided is a fuel cell including: a membrane electrode assembly; a pair of gas diffusion layers holding the membrane electrode assembly therebetween; and a pair of separators holding the membrane electrode assembly and the pair of gas diffusion layer therebetween. The separators have ribs on surfaces facing the gas diffusion layers, the ribs forming channels which are gas flow paths. A thickness t (?m) of each of the gas diffusion layers and an area occupation ratio SC (?) of the channels on the surface facing the gas diffusion layer satisfy the relationship represented by the following formula (1): 0.9>SC?55(t?103)2/1000000+0.3??(1).

Abstract: A fuel cell system determines a water blockage or a dry state of the system using voltage sensors that determine anode and cathode voltages of single fuel cells as well as a total voltage for the fuel cell system. The system also compensates for water blockages or dry states by adjusting supplies of fuel and oxidation gases to the system.

Abstract: A fuel cell stack structure includes, for example, a plurality of unit cells each having an aperture formed therethrough. A first fuel cell stack is formed by stacking the plurality of unit cells in a stacking direction and has an internal manifold opening defined by the apertures. A fluid passage within the cell for flowing a fluid that flows within the internal manifold is configured and arranged to flow the fluid in a plane generally perpendicular to the stacking direction of the unit cell. The structure also includes an external manifold having an external passage for supplying the fluid to the internal manifold, wherein the fluid flowing within the external passage creates a vortex proximal to the internal manifold by an external manifold surface facing a flow direction of the fluid.

Abstract: A fuel cell system determines a water blockage or a dry state of the system using voltage sensors that determine anode and cathode voltages of single fuel cells as well as a total voltage for the fuel cell system. The system also compensates for water blockages or dry states by adjusting supplies of fuel and oxidation gases to the system.

Abstract: A silicon carbide-based porous material containing silicon carbide particles (1) as an aggregate and metallic silicon (2), wherein the average particle diameter of the silicon carbide-based porous material is at least 0.25 time the average particle diameter of the silicon carbide particles (1), or the contact angle between the silicon carbide particles (1) and the metallic silicon (2) is acute, or a large number of secondary texture particles each formed by contact of at least four silicon carbide particles (1) with one metallic silicon (2) are bonded to each other to form a porous structure. This silicon carbide-based porous material can be sintered, in its production, at a relatively low firing temperature and, therefore, can be provided at a low production cost, at a high yield and at a low product cost.

Abstract: A silicon carbide-based porous material containing silicon carbide particles (1) as an aggregate and metallic silicon (2), wherein the average particle diameter of the silicon carbide-based porous material is at least 0.25 time the average particle diameter of the silicon carbide particles (1), or the contact angle between the silicon carbide particles (1) and the metallic silicon (2) is acute, or a large number of secondary texture particles each formed by contact of at least four silicon carbide particles (1) with one metallic silicon (2) are bonded to each other to form a porous structure. This silicon carbide-based porous material can be sintered, in its production, at a relatively low firing temperature and, therefore, can be provided at a low production cost, at a high yield and at a low product cost.