Abstract: An illustrative example system for managing hydrogen utilization in a fuel cell power plant includes a first hydrogen concentration sensor that provides an indication of a first concentration of hydrogen in a fluid flowing into an anode inlet of the power plant. A second hydrogen concentration sensor provides an indication of a second concentration of hydrogen in a fluid flowing out of an anode exit of the power plant. A processor determines a utilization of hydrogen by the power plant based on the first and second concentrations.

Abstract: An illustrative example hydrogen concentration sensor includes a first end plate. A hydrogen evolving electrode assembly that generates hydrogen is situated adjacent the first end plate and at least partially exposed through an opening through the end plate. A separator plate is between the hydrogen evolving electrode assembly and a detection electrode assembly. The separator plate includes a passage to allow a flow of hydrogen generated by the hydrogen evolving electrode assembly to the detection electrode assembly. A second end plate is situated adjacent the detection electrode assembly and includes a second opening where a portion of the detection electrode assembly is exposed to a fluid of interest to provide an indication of a concentration of hydrogen in the fluid of interest.

Abstract: An ejector receives steam at a primary inlet and natural gas at a secondary inlet. A computer responds to a signal indicating current in the load of a fuel cell as well as a signal indicating temperature of a steam reformer to move a linear actuator to control a needle that adjusts the size of the steam orifice. Reformate is fed to a separator scrubber which cools the reformate to its dew point indicated by a sensor. From that, a controller generates the fuel/carbon ratio for display and to bias a signal on a line regulating the amount of steam passing through an ejector to the inlet of the reformer. Alternatively, the reformate may be cooled to its dew point by a controllable heat exchanger in response to pressure and temperature signals.

Abstract: An illustrative example fuel cell component includes a plate with a plurality of flow channels in at least one side of the plate. Each of the flow channels has a length between an inlet and an outlet. Each of the flow channels has a width and a depth, which are transverse to the length. At least some of the flow channels include a portion near the inlet and the width or the depth of the portion is greater than the width or depth along a majority of the length of those flow channels.

Abstract: An illustrative example fuel cell reactant flow control valve assembly includes a pneumatic valve configured to allow reactant flow when the pneumatic valve is in an open condition and to prevent reactant flow when the pneumatic valve is in a closed condition. A control valve selectively allows a pressure of the reactant to provide pneumatic pressure to maintain the pneumatic valve in the open condition. The control valve selectively vents the pneumatic pressure reservoir to control a rate at which the pneumatic pressure decreases and a rate at which the pneumatic valve changes from the open condition to the closed condition.

Abstract: An illustrative method of making a fuel cell component includes obtaining at least one blank plate including graphite and a polymer; establishing a temperature of the blank that is sufficient to maintain the polymer in an at least partially molten state; and applying a compression molding force to the blank until the polymer is essentially solidified to form a plate including a plurality of channels on at least one side of the plate. The blank plate has a central area having a first thickness. The blank plate also has two generally parallel edges on opposite sides of the central area. The edges have a second thickness that is greater than the first thickness.

Abstract: An illustrative example fuel cell assembly includes a plurality of fuel cells arranged in a stack including a first end fuel cell near a first end of the stack and a second end fuel cell near a second end of the stack. Each of the fuel cells includes a matrix containing an electrolyte, an anode and a cathode on opposite sides of the matrix, and respective flow fields adjacent the anode and the cathode. An electrolyte supply associated with the anode flow field of the first end fuel cell includes a porous material containing electrolyte. An electrolyte collector associated with the cathode flow field of the second end fuel cell includes a porous material configured to collect electrolyte from at least the cathode of the second end fuel cell.

Abstract: An illustrative example fuel cell power plant includes a cell stack assembly having a plurality of fuel cells configured to generate electricity based on an electrochemical reaction. The power plant includes a capacitor, a plurality of inverters, and at least one controller that is configured to control the plurality of inverters in a first mode and a second mode. The first mode includes the cell stack assembly associated with at least one of the inverters. A cell stack assembly and the associated inverter provide real power to a load external to the fuel cell power plant in the first mode. The second mode includes at least a second one of the inverters associated with the capacitor. The capacitor and the second one of the inverters selectively provide reactive power to or receive reactive power from a grid external to the fuel cell power plant in the second mode.

Abstract: A fuel cell includes a fuel cell stack. A pressure plate is arranged on one side of the fuel cell stack. The pressure plate includes a hole, and a tie rod assembly has a tie rod received in the hole. A nut with a conical surface is secured to the tie rod. An isolator is arranged in the hole between the tie rod assembly and the pressure plate. The isolator has a conical portion, and the conical surface engages the conical portion to provide a conical interface. The tie rod assembly applies a clamp load on the fuel cell stack via the conical interface.