Abstract: An end unit for a fuel cell stack is provided. The end unit includes a main body having a cavity and a substantially impermeable barrier disposed thereon to militate against heat transfer within the end unit and minimize a cost of insulating the end unit. A fuel cell system and a method of fabricating the end unit for use in a fuel cell system are also provided.

Abstract: A bipolar plate includes angled facets oriented to form V-shaped projections on the plate edge. Liquid leaving the reactant channels is drawn back into the V-shaped grooves of the projections, leaving no liquid to obstruct the channel exit openings. The bipolar plate includes one portion of the bipolar plate offset from another portion of the bipolar plate so as to expose the reactant channels. The liquid is drawn toward the end portions of the reactant channels by capillary forces, while the gas flows can exit near the beginning of the offset portion. A fuel cell stack includes angled facets that are rotated to lie in the plane of the bipolar plate edges. The edges are chamfered so the channel exit openings of the reactant channels are at the tip portions thereof, thus allowing the liquid to flow away from the channel exit openings and the gas to exit freely.

Abstract: A model uses various operating characteristics of a fuel cell to predict the relative humidity profile that is occurring within the fuel cell as a function of the reaction progress. The model is used to predict the relative humidity profile that will occur in response to changes to one or more of the operating characteristics of the fuel cell. A high frequency resistance of the fuel cell can also be used as a measure that is indicative of the humidity within the fuel cell. The model and/or the high frequency resistance can be used in a closed-loop feedback system to control the operation of the fuel cell to maintain the humidification of the MEA and fuel cells within a desired range to achieve a desired fuel cell performance.

Abstract: An integrated charge air heat exchanger for use in a vehicle fuel cell system is provided. The integrated charge air heat exchanger includes a plurality of coolant conduits adapted for a coolant fluid to flow therethrough. The integrated charge air heat exchanger further includes a plurality of heating elements and a plurality of fin elements. One heating element is disposed on a first surface of each of the coolant conduits, and one of the fin elements is disposed on a second surface of each of the coolant conduits. A method for heating the coolant fluid in a first operational mode and cooling a charge air stream in a second operational mode is also provided.

Abstract: A model uses various operating characteristics of a fuel cell to predict the relative humidity profile that is occurring within the fuel cell as a function of the reaction progress. The model is used to predict the relative humidity profile that will occur in response to changes to one or more of the operating characteristics of the fuel cell. A high frequency resistance of the fuel cell can also be used as a measure that is indicative of the humidity within the fuel cell. The model and/or the high frequency resistance can be used in a closed-loop feedback system to control the operation of the fuel cell to maintain the humidification of the MEA and fuel cells within a desired range to achieve a desired fuel cell performance.

Abstract: A model uses various operating characteristics of a fuel cell to predict the relative humidity profile that is occurring within the fuel cell as a function of the reaction progress. The model is used to predict the relative humidity profile that will occur in response to changes to one or more of the operating characteristics of the fuel cell. A high frequency resistance of the fuel cell can also be used as a measure that is indicative of the humidity within the fuel cell. The model and/or the high frequency resistance can be used in a closed-loop feedback system to control the operation of the fuel cell to maintain the humidification of the MEA and fuel cells within a desired range to achieve a desired fuel cell performance.

Abstract: A bipolar plate for a fuel cell is disclosed including a first unipolar plate having an active surface with a plurality of flowfield channels formed therein. The first unipolar plate further includes an inlet header disposed at a first end of the unipolar plate that is in communication with the active surface, and an outlet header disposed at a second end of the unipolar plate having an exhaust opening formed therethrough. A peripheral edge of the exhaust opening is chamfered and is also in communication with the active surface. The chamfered exhaust opening forms a water removal channel in the bipolar plate. A fuel cell stack including the bipolar plate is also disclosed.

Abstract: A bipolar plate for use in a fuel cell stack includes a first plate having a first coolant face with a first set of coolant channels formed therein. A second plate has a second coolant face with a second set of coolant channels formed therein. The first and second coolant faces are adjacent to one another to intermittently cross-link the first and second sets of coolant channels over a region of the first and second coolant faces.

Abstract: An end unit for a fuel cell stack is provided. The end unit includes a main body having a cavity and a substantially impermeable barrier disposed thereon to militate against heat transfer within the end unit and minimize a cost of insulating the end unit. A fuel cell system and a method of fabricating the end unit for use in a fuel cell system are also provided.

Abstract: An integrated charge air heat exchanger for use in a vehicle fuel cell system is provided. The integrated charge air heat exchanger includes a plurality of coolant conduits adapted for a coolant fluid to flow therethrough. The integrated charge air heat exchanger further includes a plurality of heating elements and a plurality of fin elements. One heating element is disposed on a first surface of each of the coolant conduits, and one of the fin elements is disposed on a second surface of each of the coolant conduits. A method for heating the coolant fluid in a first operational mode and cooling a charge air stream in a second operational mode is also provided.

Abstract: A bipolar plate includes angled facets oriented to form V-shaped projections on the plate edge. Liquid leaving the reactant channels is drawn back into the V-shaped grooves of the projections, leaving no liquid to obstruct the channel exit openings. The bipolar plate includes one portion of the bipolar plate offset from another portion of the bipolar plate so as to expose the reactant channels. The liquid is drawn toward the end portions of the reactant channels by capillary forces, while the gas flows can exit near the beginning of the offset portion. A fuel cell stack includes angled facets that are rotated to lie in the plane of the bipolar plate edges. The edges are chamfered so the channel exit openings of the reactant channels are at the tip portions thereof, thus allowing the liquid to flow away from the channel exit openings and the gas to exit freely.

Abstract: A bipolar plate for a fuel cell is disclosed including a first unipolar plate having an active surface with a plurality of flowfield channels formed therein. The first unipolar plate further includes an inlet header disposed at a first end of the unipolar plate that is in communication with the active surface, and an outlet header disposed at a second end of the unipolar plate having an exhaust opening formed therethrough. A peripheral edge of the exhaust opening is chamfered and is also in communication with the active surface. The chamfered exhaust opening forms a water removal channel in the bipolar plate. A fuel cell stack including the bipolar plate is also disclosed.

Abstract: A multiple serpentine tube heat exchanger having side-by-side arranged serpentine-shaped passageways each extending across the core and a mixing chamber connecting one such passageway to at least one other. The passageway constituting the back of the heat exchanger core has an enlarged internal surface area relative to the passageway constituting the face of the heat exchanger core. Microgrooving of the passageway can be used to further enhance heat transfer.

Abstract: A one-piece combination radiator tank and oil cooler for an automotive vehicle comprises a molded polymer structure of double wall construction such that the space between the walls is an oil cooler reservoir which shares a common wall with the coolant reservoir of the radiator tank. The heat from the oil reservoir is transferred to the coolant reservoir. Heat transfer across the common wall is enhanced by using high surface area shapes and by using surface features that promote good heat transfer. The inlet and outlet fittings are also molded polymer. The whole assembly is molded as one piece or as a very few pieces which are bonded together.

Abstract: An oil cooler and a radiator hose are combined in an all polymer structure. Generally concentric hoses provide two coolant paths with the wall of the inner hose providing heat transfer from one fluid to the other. The hoses are flexible or can be formed to conform to desired radiator hose routing. The hoses have deflectable vanes extending from their walls into the fluids to flex according to flow rate. The vanes induce turbulence to improve the thermal transfer especially at low flow rates but deflect at high flow rates to minimize pressure drop due to the vanes.