The transient behavior of the cell polarization and transport phenomena of polymer-electrolyte fuel cells (PEFCs) has been investigated using the Galerkin Finite Element Method (GFEM). The effects of a linear ramp in current density on cell potential, temperature, water concentration, and the flux of water leaving the cell are reported. Simulations indicate that the time constant for the fuel cell to reach steady state after a sudden change in load or current density is on the order of an hour. Model predictions further indicate that steady state is reached more quickly during a ramp up in current density; considerably longer times are needed to reach steady state during a ramp down.
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