In-service fuel cell performance recovery

摘要

The performance of a fuel cell power plant that decays, in an electric vehicle which makes frequent starts, is recovered by partially shutting down (65-67) the power plant. Recovery is enabled by a recovery enable flag (25) upon conditions such as vehicle using (22) low or no power (16), vehicle speed at or near zero (22), electric storage SOC above a threshold (23), and no recovery (19) during the last half-hour (or other duration). The recovery restart resets a timer (79) to ensure (19) that recovery is not attempted too often. The power plant then remains in a recovery stand-by mode (72) until a recovery restart flag (35) is set to 1 (74). The restart causes start-up of the fuel cell power plant (50, 52, 55), reaching an operational mode (57).

主权项

1. A method comprising:
operating a fuel cell power plant that provides electric power to an electrically propelled vehicle in a manner to recover fuel cell stack performance when the electrically propelled vehicle is temporarily not moving and is demanding either a small amount of power or no power at all, wherein recovering fuel cell stack performance comprises, in order, disconnecting the electrically propelled vehicle from an electric power output of the fuel cell power plant, connecting one or more voltage limiting devices to the electric power output of the fuel cell power plant, shutting off oxidant supply to cathodes of the fuel cell power plant, and shutting off fuel supply to anodes of the fuel cell power plant, and once fuel cell stack performance has been recovered, restoring normal operation of the fuel cell power plant in response to one or more conditions selected from a) a drive system of the electrically propelled vehicle consuming power in excess of a threshold amount, b) a vehicle speed exceeding a speed threshold, and c) an electric energy storage device which receives electric charge from the fuel cell power plant having a state of charge less than a threshold state of charge.