Passive electrode blanketing in a fuel cell

A fuel cell module, comprising:

• a fuel cell including a first electrode, a second electrode and an electrolyte medium arranged between the first and second electrodes, wherein during normal operation the first electrode is provided with a first reactant and the second electrode is provided with a first mixture containing a second reactant and a non-reactive agent;
• a parasitic load that is connectable across the first and second electrodes;
• a first reactant supply, fluidly connectable to the anode electrode, for supplying first reactant to the anode electrode;
• a side stream fluidly connectable to the first reactant supply and the anode electrode;
• a reactant reservoir, fluidly connectable to the side stream, for storing an amount of the first reactant suitable for a shutdown process of the fuel cell module, whereby, in use when the fuel cell module is shutdown, the stored amount of the first reactant is drawn from the reactant reservoir and electrochemically reacts with an amount of the second reactant remaining in the fuel cell module, to electrochemically consume the first and second reactants, thereby leaving a second mixture that substantially comprises the non-reactive agent;
• and
• a pressure generating device, fluidly connectable to the side stream and positioned upstream of the reactant reservoir, for pressurizing and delivering the first reactant from the first reactant supply to the reactant reservoir.

A reactant supply system for a fuel cell stack, having an anode inlet, an anode outlet, a cathode inlet and a cathode outlet, the reactant supply system comprising:

• a first reactant supply port connectable in use to the anode inlet of the fuel cell stack;
• a second reactant supply port connectable in use to the cathode inlet, for supply of a mixture comprising the second reactant and a non-reactant agent;
• a parasitic load that is connectable across the anode and cathode electrodes of the fuel cell stack;
• a side stream fluidly connectable to the first reactant supply line;
• a reactant reservoir, fluidly connectable to the side stream, for storing an amount to the first reactant suitable for a shutdown process of the fuel cell stack, whereby, in use, when the fuel cell stack is shutdown, the stored amount of the first reactant is drawn from the reactant reservoir and electrochemically reacts with the secondary reactant in the fuel cell module, to electrochemically consume the first and second reactants, thereby leaving a second mixture that substantially comprises the non-reactive agent;
• and
• a pressure generating device, fluidly connectable to the side stream for pressurizing delivering the first reactant to the reactant reservoir.

A process for shutting down a fuel cell, the fuel cell including a first electrode, a second electrode and an electrolyte membrane arranged between the first and second electrodes, the process comprising during normal operation:

• providing the first electrode with a first reactant and the second electrode with a first mixture containing a second reactant and a non-reactive agent, and;
• pressurizing a portion of the first reactant and storing the first reactant in a reactant reservoir;
• and
• the process further comprising at shutdown:
• stopping an inflow of the first reactant into the first electrode;
• cutting-off power to supporting balance of plant elements;
• drawing current through a parasitic load connectable across the first and second electrodes;
• permitting the stored first reactant to flow to the first electrode for the electrochemical consumption of a remaining amount of a second reactant;
• wherein the first reactant electrochemically reacts with the remaining amount of the second reactant, thereby leaving a second mixture that substantially comprises the non-reactive agent.