Abstract: A flow field geometry formed in a separator plate of a fuel cell includes a plurality of straight inlet legs including a first lateral inlet leg laterally offset from a first inlet leg and a dividing junction associated with each of the plurality of straight inlet legs. The dividing junction divides a straight inlet leg into a plurality of branched legs. A number of a first set of branched legs associated with the first lateral inlet leg is greater than a number of a set of branched legs associated with the first inlet leg.

Abstract: A hydrogen fuel cell stack has at least two segments of fuel cells each having reactant gas passages. The reactant gas passages of each fuel cell in each segment are arranged in parallel with each other. Flow of fuel cell fluids is in a gravity assisted downward direction. Gravity assisted flow directs water formed in each cell to lower removal points of the stack segments. Adjacent segments are separated by either a separator segment formed as an integral unit with the stack or the segments are joined and an external piping system directs flow to differing stack areas. A cathode flow enters at a first stack end and a hydrogen anode flow enters the stack at an opposite end, such that cathode and anode flows are counter-current to each other. A coolant flow is normally injected adjacent to and flows parallel with the cathode flow, but can also be directed by the piping system to any or all segments in series or parallel.

Abstract: A fuel cell stack has at least two segments of fuel cells each having reactant gas passages. Each of the cells in each segment is arranged such that the reactant gas passages of each cell are in parallel with each other cell. Flow of fuel cell fluids, normally in a gaseous state on the anode and cathode side of each cell, is in a gravity assisted downward direction. Gravity assisted flow directs water formed in each cell to lower removal points of the stack segments. Each pair of segments is separated by a separator segment having a separator channel, the separator segment forming an integral unit of the stack. Each separator channel redirects the entire flow of each fluid within the stack from the bottom of an upstream segment to the top of a next or downstream segment, without reacting the fluid, controlling relative humidity between stack segments.

Abstract: Fuel cell stack having a plurality of liquid-cooled, bipolar plates separating one cell from the next. Coolant inlet and outlet manifolds are defined, in part, by surfaces of the bipolar plates, and respectively supply coolant to, and remove coolant from, the bipolar plates. The surfaces of the bipolar plates that define the coolant manifolds and confront the coolant in the manifolds are coated with a non-conductive coating to reduce shunt current flow through the coolant.

Abstract: A current-collecting plate of a PEM fuel cell has a reaction gas flow-field comprising a plurality of flow-channels each having an inlet leg communicating with a fuel supply manifold, an exit leg communicating with a fuel exhaust manifold, and a branched midsection intermediate the inlet and exit legs.

Abstract: A fuel cell stack has at least two segments of fuel cells each having reactant gas passages. Each of the cells in each segment is arranged such that the reactant gas passages of each cell are in parallel with each other cell. Flow of fuel cell fluids, normally in a gaseous state on the anode and cathode side of each cell, is in a gravity assisted downward direction. Gravity assisted flow directs water formed in each cell to lower removal points of the stack segments. Each pair of segments is separated by a separator segment having a separator channel, the separator segment forming an integral unit of the stack. Each separator channel redirects the entire flow of each fluid within the stack from the bottom of an upstream segment to the top of a next or downstream segment, without reacting the fluid, controlling relative humidity between stack segments.

Abstract: A bipolar plate assembly for use in a PEM fuel cell having an anode plate and a cathode plate together to define flow fields on the exposed faces thereof and a coolant volume therebetween. Each of the flow fields have a transverse inlet leg in fluid communication with the inlet header, a serpentine flow field extending from the transverse inlet leg and a transverse exhaust leg in fluid communication with the exhaust header. The plates further define a tortuous coolant flow path in the coolant volume.

Abstract: Fuel cell stack having a plurality of liquid-cooled, bipolar plates separating one cell from the next. Coolant inlet and outlet manifolds are defined, in part, by surfaces of the bipolar plates, and respectively supply coolant to, and remove coolant from, the bipolar plates. The surfaces of the bipolar plates that define the coolant manifolds and confront the coolant in the manifolds are coated with a non-conductive coating to reduce shunt current flow through the coolant.