Water transfer means (86) transfers fuel cell product water from a cathode
water transport plate (34) to an anode water transport plate (23) of the
same or a different fuel cell, wholly within a fuel cell stack (50),
(disposed within each fuel cell of a fuel cell stack (50)). The water
transfer means may be a very high permeability proton exchange membrane
(21a), a water transfer band (90) such as silicon carbide particles, a
porous water transfer zone (107), with or without a flow restrictor
(109), internal water manifolds (112, 113) which extend through an entire
fuel cell stack, or internal manifolds (112a, 112b, 112c, 112d, 113a,
113b, 113c, 113d) which extend only through groups of cells between solid
plates (71). As an example, 90% product water may be removed as vapor in
oxidant exhaust, 30% may be transferred through the water transfer means
(86) from cathode water transport plates to anode water transport plates,
of which 20% may flow from the anode to the cathode, the net result of
osmosis and proton drag, and 10% may exit the anode water transport
plates as liquid water.