Abstract: Described herein are methods, articles, and systems relating to planar fuel cells having simplified structures. The planar fuel cells include current collection circuits that are disposed between a planar array of unit fuel cells and associated cover layers. The associated cover layers are porous, dielectric, and define a network of interconnected pores.

Abstract: An adjustable flow field and flow regulation method for an electrochemical device such as field preferably includes a plurality of flow paths between an inlet and an outlet and a plurality of microvalves for regulating fluid flow through the flow paths in response to changes in the operating states of the fuel cell, such as changes in power output or temperature. For example, adjustment of the microvalves may restrict the number of flow paths through which fluid is flowing to alter the effective active area and current density of the flow field. The valves may be selectively opened or closed, either entirely or partially, to maintain a minimum pressure drop between the inlet and outlet. Alternatively or additionally, adjustment of the valves may alter the direction of fluid flow through at least some of the flow paths.