Abstract: A fuel cell stack is provided with an outlet side oxygen-containing gas communication hole. First and second oxygen-containing gas flow passage grooves are provided in the direction of the gravity while meandering in the horizontal direction on a surface of a first separator. The second oxygen-containing gas flow passage grooves communicate with the outlet side oxygen-containing gas communication hole via second oxygen-containing gas connecting flow passages. The lowest position of the second oxygen-containing gas flow passage grooves 44 in the direction of gravity is higher than the bottom of the outlet side oxygen-containing gas communication hole 38b by the height h.

Abstract: A fuel cell stack includes a first end power generation unit and a first dummy unit, adjacent to a power generation unit provided at one end of a stack body in a stacking direction. The first end power generation unit includes a fourth separator having the same structure as a first separator of the power generation unit, and includes a fifth separator and a sixth separator having the same structure as a second separator and a third separator. In effect, common separators are used for the fifth separator and the sixth separator by changing a pin of a molding die or changing part of a seal die.

Abstract: A cell assembly is formed by stacking a first unit cell and a second unit cell to each other. The first unit cell includes a first unified body, and the second unit cell includes a second unified body. In the cell assembly, the first and second unit cells have structures different from each other.

Abstract: A fuel cell according to the present invention includes a power generation unit. The power generation unit is formed by stacking a first metal separator, a first membrane electrode assembly, a second metal separator, a second membrane electrode assembly, and a third metal separator. The number of flow grooves in a first oxygen-containing gas flow field is different from the number of flow grooves in a second oxygen-containing gas flow field. The first oxygen-containing gas flow field and the second oxygen-containing gas flow field have the same length, and the flow grooves in the first oxygen-containing gas flow field and the flow grooves in the second oxygen-containing gas flow field have the same depth.

Abstract: Each of power generation units of a fuel cell according to the present invention is formed by stacking a first metal separator, a first membrane electrode assembly, a second metal separator, a second membrane electrode assembly, and a third metal separator together. The power generation unit has therein a first oxygen-containing gas flow field, a first fuel gas flow field, a second oxygen-containing gas flow field, and a second fuel gas flow field. The number of flow grooves in the first oxygen-containing gas flow field is different from that of flow grooves in the second oxygen-containing gas flow field, and the number of flow grooves in the first fuel gas flow field is different from that of flow grooves in the second fuel gas flow field.

Abstract: A cell assembly is formed by stacking a first unit cell and a second unit cell to each other. The first unit cell includes a first unified body, and the second unit cell includes a second unified body. In the cell assembly, the first and second unit cells have structures different from each other.

Abstract: A fuel cell stack (10) includes a first sub-stack (12), a second sub-stack (14), and a third sub-stack (16) disposed in the flow direction of an oxidizing gas. An intermediate plate (18a) is interposed between the first and second sub-stacks (12, 14), and an intermediate plate (18b) is interposed between the second and third sub-stacks (14, 16). In this fuel stack (10), the flow of an oxidizing gas is set such that the oxidizing gas flows in series in the direction from the first sub-stack (12) to the third sub-stack (16). Between the sub-stacks additional oxidizing gas supplies (70,74) are provided through which oxidizing gas of lower humidity than the humidity of the oxidizing gas entering the first sub-stack is supplied. This arrangement allows an efficient management of the humidity water content of the oxidizing gas with sufficient moisturizing of the solid polymer membrane whilst avoiding excessive condensation of water vapour within the stack.

Abstract: A first metal separator of one of adjacent power generation cells and a second metal separator of the other of the adjacent power generation cells are directly stacked together to form a coolant flow field. The first metal separator has a press line protruding toward the coolant flow field, between a fuel gas flow field and an inlet buffer. The second metal separator has a press line protruding toward the coolant flow field, between an oxygen-containing gas flow field and an inlet buffer. The press lines contact each other to limit flow of the coolant into a back surface buffer.

Abstract: A fuel cell includes a membrane electrode assembly, and first and second separators. A first insulating bushing is attached to a first positioning hole of a first separator, and a second insulating bushing is attached to a second positioning hole of the second separator. An inner wall of the first insulating bushing is fitted to an outer wall of the second insulating bushing for positioning the first and second separators such that the first and second separators are insulated from each other.

Abstract: A cell assembly includes a first unit cell and a second unit cell which are stacked to each other. The first unit cell has a first unified body, and the second unit cell has a second unified body. A plurality of oxidizing gas passages and a plurality of fuel gas passages are provided in the cell assembly. The oxidizing gas passages in the first unit cell and the oxidizing gas passages in the second unit cell are communicated in series to each other. The fuel gas passages in the first unit cell and the fuel gas passages in the second unit cell are communicated in series to each other.

Abstract: A power generation cell includes a membrane electrode assembly and first and second metal separators sandwiching the membrane electrode assembly. The first metal separator is a thin metal plate. A first seal member is formed integrally around the outer end of the first metal separator. A portion defining an orifice is provided in an outer marginal region of the first metal separator. The thickness H1 of the first seal member in the area covering the portion defining the orifice is larger than the thickness of the H2 of the first seal member in the area covering other portions.

Abstract: A coolant flow field is formed on a surface of a second metal separator. Further, a rubber bridge dividing the coolant flow field and a coolant supply passage is formed on the surface. The rubber bridge includes a plurality of channels connecting the coolant flow field and the coolant supply passage, a plurality of grooves between the channels, and a partition closing the grooves to prevent the flow of a coolant in the respective grooves.

Abstract: A casing includes end plates and first through fourth side plates. The first and third side plates are short, and the second and fourth side plates are long. At least cross sectional areas or shapes of the first through fourth side plates are determined such that the sides of the end plates have substantially the same deflection in the stacking direction.

Abstract: A fuel cell stack is provided with an outlet side oxygen-containing gas communication hole. First and second oxygen-containing gas flow passage grooves are provided in the direction of the gravity while meandering in the horizontal direction on a surface of a first separator. The second oxygen-containing gas flow passage grooves communicate with the outlet side oxygen-containing gas communication hole via second oxygen-containing gas connecting flow passages. A porous water-absorbing tube, which is used to discharge water to the outside of the fuel cell stack in accordance with the capillary phenomenon and the difference in pressure of air, is provided for the outlet side oxygen-containing gas communication hole.

Abstract: A fuel gas inlet, a fuel gas outlet, an oxygen-containing gas inlet, an oxygen-containing gas outlet, and other components, which are disposed at upper and lower portions at both ends in the lateral direction, are provided in a first fuel cell stack. A plurality of cooling medium inlets, a plurality of cooling medium outlets, and other components are provided at lower portions on the long side and at upper portions on the long side respectively. A cooling medium flows from the lower portions to the upper portions through cooling medium flow passages to cool the power generation surface smoothly and reliably.

Abstract: A seal member is formed integrally on surfaces of a metal separator of a fuel cell. The seal members include an outer seal provided near the outer edge of the separator, and an inner seal spaced inwardly from the outer seal by a predetermined distance. When a load is applied to the outer seal and the inner seal in a stacking direction, the outer seal and the inner seal are deformed substantially equally in the stacking direction to the same extent.

Abstract: A fuel cell includes a membrane electrode assembly and first and second separators for sandwiching the membrane electrode assembly. A serpentine oxygen-containing gas flow field is formed on a surface of the first separator. A seal member is provided around the oxygen-containing gas flow field, i.e., around the anode. Filling seals are provided in a clearance between the seal member and the cathode at positions where the leakage of an oxygen-containing gas is likely to occur.

Abstract: A fuel cell includes a plurality of metal clip members for holding outer regions of first and second metal separators at a plurality of positions. Each of the metal clip member includes a side plate and first and second holding portions. The side plate is curved at opposite ends, and the first and second holding portions are extending from the opposite ends of the side plate. The first and second holding portions generates a predetermined elastic force for holding the first and second metal separators. The outer ends of the first and second metal separators are covered by insulating sections, and the insulating sections are held between the first and second holding portions so that the entire unit cell is tightened by the predetermined elastic force.

Abstract: A membrane electrode assembly includes an anode, a cathode, and a solid polymer electrolyte membrane interposed between the anode and the cathode. The membrane electrode assembly has a substantially rectangular shape as a whole. Extensions extend outwardly from four corners of the membrane electrode assembly. Each of the extensions has an inclined end to have a substantially triangle shape. The membrane electrode assembly has a substantially rectangular power generation area.

Abstract: A fuel gas inlet, a fuel gas outlet, an oxygen-containing gas inlet, an oxygen-containing gas outlet, and other components, which are disposed at upper and lower portions at both ends in the lateral direction, are provided in a first fuel cell stack. A plurality of cooling medium inlets, a plurality of cooling medium outlets, and other components are provided at lower portions on the long side and at upper portions on the long side respectively. A cooling medium flows from the lower portions to the upper portions through cooling medium flow passages to cool the power generation surface smoothly and reliably.