Four-fluid bipolar plate for fuel cell

A four-fluid bipolar plate for a fuel cell, comprising:

• a nonporous sub-plate comprising a first water management side, an opposing second water management side, and an internal coolant passage therebetween;
• the first water management side having a first recessed region over an area approximately equal to the active area, and the second water management side having a second recessed region over an area approximately equal to the active area;
• a first porous sub-plate nested and sealed in the first recessed region of the nonporous sub-plate, the first porous sub-plate comprising a first reactant side and an opposing first water management side, the first water management side in fluid communication with the first water management side of the nonporous sub-plate;
• and
• a second porous sub-plate nested and sealed in the second recessed region of the nonporous sub-plate, the second porous sub-plate comprising a second reactant side and an opposing second water management side, the second water management side fluid communication with the second water management side of the nonporous sub-plate.

A four-fluid fuel cell power plant, comprising:

• a stack of bipolar plates, each bipolar plate comprising:
• a nonporous sub-plate comprising a water management side, an opposing reactant side, and an internal coolant passage therebetween;
• the water management side having a recessed region over an area approximately equal to the active area;
• a porous sub-plate nested and sealed in the recessed region of the nonporous sub-plate, the porous sub-plate comprising a reactant side and an opposing water management side, the water management side in fluid communication with the water management side of the nonporous sub-plate, the porous sub-plate further comprising a plurality of pores adapted to permit liquid transport through the pores during operation while preventing reactant gas transport, and
• a unitized electrode assembly disposed between the reactant side of each bipolar plate;
• a fuel reactant supply and return system to supply a fuel to a fuel supply manifold and remove unconsumed fuel through a fuel return manifold;
• an oxidant reactant supply and return system to supply an oxidant to an oxidant supply manifold and remove excess oxidant through an oxidant return manifold;
• an external circulating water management loop in fluid communication with the water management sides of the nonporous sub-plate and the porous sub-plate, the water in the management loop entering the bipolar plate through a water management supply manifold and exiting through a water management return manifold;
• an isolated coolant loop in fluid communication with the bipolar plate internal coolant passage, the coolant loop comprising a pump, a coolant supply manifold wherein coolant enters the bipolar plate, coolant passages to pick up sensible heat, a coolant return manifold wherein coolant exits the bipolar plate, and a heat exchange apparatus to reject the sensible heat.