Abstract: A heat regulating system for an electrochemical conversion assembly. In one embodiment, the electrochemical conversion assembly is a fuel cell, and the device includes one or more fluid-manipulating components to vary the amount of a coolant or related heat regulating fluid used to maintain a preferred temperature in the fuel cell. Preferred fuel cell operating temperatures can be more easily achieved by selectively bypassing a portion of the coolant around the fuel cell during certain temperature or power demand regimes. A controller can be used to monitor and selectively vary the extent to which at least one of these components modifies the flow of fluid past the fuel cell.

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 thermal management system of an electrochemical engine comprises a radiator provided with a wicking mechanism, a coolant pump fluidly connected to the radiator, a water tank, and a water pump. The water tank is located in the void spaces around fuel storage tanks, and may be filled directly or with reclaimed water from a vapor by-product of the electrochemical engine. The water pump is operable to supply water from the water tank to the wicking mechanism during peak power and/or hot day conditions. Moisture in the vapor by-product may be condensed with the excess cooling capacity of the radiator under less severe cooling conditions. Under freezing conditions, exhaust or coolant from the electrochemical engine may be used to unfreeze water in the tank and wicking mechanism supply lines.

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.