Abstract: The thermal profile of one or more fuel cells (10) cooled by coolant flowing in coolant flow passageways (30, 31, 33, 34, 37-41, 45-50) is tailored by providing selected material (65, 68) adjacent a portion (33b) of the coolant passageway; the selected material has a different thermal transfer characteristic than material surrounding other portions of the coolant passageway. The material may be more insulative or more conductive. The material may be wrapping (65), such as shrink wrap, about a coolant tube, or it may be altered material (68) in a molding material.

Abstract: A fuel cell is disclosed that includes an electrode assembly arranged between a cathode and an anode. The anode and cathode have lateral surfaces adjoining lateral surface of the electrode assembly and respectively include fuel and oxidant flow fields. Interfacial seals are not arranged between the lateral surfaces. Instead, a sealant is applied to the anode, the cathode and the electrode assembly to fluidly separate the fuel and oxidant flow fields. In one example, the adjoining lateral surfaces are in abutting engagement with one another. The sealant is applied in a liquid, uncured state to perimeter surfaces of the electrode assembly, the anode and the cathode that surround the lateral surfaces.

Abstract: The thermal profile of one or more fuel cells (10) cooled by coolant flowing in coolant flow passageways (30, 31, 33, 34, 37-41, 45-50) is tailored by providing selected material (65, 68) adjacent a portion (33b) of the coolant passageway; the selected material has a different thermal transfer characteristic than material surrounding other portions of the coolant passageway. The material may be more insulative or more conductive. The material may be wrapping (65), such as shrink wrap, about a coolant tube, or it may be altered material (68) in a molding material.

Abstract: An auxiliary load (148) for a fuel cell stack (102) is alternatively connected and disconnected from the fuel cell external circuit (177, 178) by a switch (200) in response to a switch control (201), repetitively, during startup and shutdown. The switch may be an insulated gate bipolar transistor (208) which is turned on and off by hunting between an upper limit voltage (207) and a lower limit voltage (208), which may be performed by compare circuits (205, 206), by the controller (202), or by commercially available voltage responsive hysteresis switches. Schedules of duty cycle as a function of cell stack voltage for startup (212) and shutdown (213) control a pulse width modulator (215) which operates the switch. Controls (229, 231) may limit the modulation so that the auxiliary load does not overheat, in response to temperature (221) of the load or a voltage/power model (235). The auxiliary load may comprise a heater in a water accumulator (247), an air intake (257) or an enthalpy recovery device (262).