FUEL CELL STACK

Abstract

A fuel cell stack includes stacked individual cells. Each individual cell has a power generation unit, a frame having a receiving hole, and two separators. Each separator has a surface facing the power generation unit. The surface has a gas passage. The gas passage has first extensions and a second extension. A separation rib is provided between two of the first extensions, which are connected to each other by the second extension. The separation rib has a base in contact with a corresponding one of gas diffusion layers of the power generation unit, and a projection protruding from the base into the corresponding gas diffusion layer. The projection has an opposite end opposite an inner surface of the receiving hole. A pressure loss increasing portion is provided at a boundary between the opposite end and the inner surface of the receiving hole.

Claims

[1] Fuel cell stack (10) comprising stacked individual cells (20), wherein each of the individual cells (20) has the following: a power generation unit (30) comprising a membrane electrode assembly (31) and two gas diffusion layers (32, 33), the gas diffusion layers (32, 33) centering the membrane electrode assembly (31); a frame (40) having a receiving hole (41) that receives the power generation unit (30); and two separators (50) which take the power generation unit (30) and the frame (40) in the middle, each of the separators (50) of the single cell (20) has a surface facing the power generation unit (30), wherein the surface facing the power generation unit (30) has a gas passage (60) through which reactant gas flows, the gas passage (60) has the following: first extensions (Lg1, Lg2, Lg3) arranged parallel to each other and in which the reactant gas flows in opposite directions; and a second extension (Tg1, Tg2) connecting ends of two of the parallel first extensions (Lg1, Lg2, Lg3), a separating rib (70) is provided between the two first extensions (Lg1, Lg2, Lg3) which are connected to each other by the second extension (Tg1, Tg2), the separating rib (70) separating the two first extensions (Lg1, Lg2, Lg3) from each other, the separating rib (70) has the following: a base (71) in contact with a corresponding one of the two gas diffusion layers (32, 33) of the power generation unit (30) and extending along the first extensions (Lg1, Lg2, Lg3); and a projection (74) which projects from the base (71) into the corresponding one of the two gas diffusion layers (32, 33) and extends along the first extensions (Lg1, Lg2, Lg3), the projection (74) has an opposite end (76) which is opposite an inner surface of the receiving hole (41), and a pressure loss increasing portion (P) is provided at a boundary between the opposite end (76) and the inner surface of the receiving hole (41), wherein the pressure loss increasing portion (P) causes a pressure loss of the reactant gas flowing beyond the opposite end (76) between the two first extensions (Lg1, Lg2, Lg3) to be higher than a pressure loss of the reactant gas flowing through the two first extensions (Lg1, Lg2, Lg3). [2] Fuel cell stack (10) according to claim 1, wherein the pressure loss increasing section (P) is defined by a gap (G) between the opposite end (76) and the inner surface of the receiving hole (41) and a cross-sectional area of the gap (G) is smaller than a cross-sectional flow area of each of the two first extensions (Lg1, Lg2, Lg3). [3] The fuel cell stack (10) according to claim 1 or 2, wherein the opposite end (76) extends in an arrangement direction of the two first extensions (Lg1, Lg2, Lg3). [4] The fuel cell stack (10) according to any one of claims 1 to 3, wherein the projection (74) has a width that is constant in a longitudinal direction of the projection (74) over the entirety of the projection (74). [5] Fuel cell stack (10) according to one of claims 1 to 4, wherein the first extensions (Lg1, Lg2, Lg3) extend while being twisted in a wave-like manner, and the base (71) and the projection (74) extend along the first extensions (Lg1, Lg2, Lg3) while being wound in a wave-like manner.

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