Multiphysics 3D CFD simulations are performed to analyze and quantify the impact of flow-field design on the performance relevant cell internal humidity, temperature and current distributions in a single-cell configuration. For this purpose, the water concentration, temperature and reaction current density distribution patterns obtained in a zero-gradient configuration with straight anode/cathode flow-channels are compared to the simulated results obtained for a bipolar plate with meander-shaped channels. 3D-CFD simulations are performed for the original JRC clamping device [1] to provide reference data for the underlying zero gradient configuration. The simulated performance of the zero-gradient cell is validated by comparison of the U-I curves with their measured counterparts. To create the cathode flow conditions aimed at resulting in pronounced cell internal temperature and humidity gradients, a dedicated bipolar plate with a meander shaped channel [2] is developed and again analyzed using 3D-CFD simulation. The simulation results clearly illustrate the spatial variations in current, concentration, and temperature distribution for the high-gradient flow conditions, which in turn promote accelerated material degradation (see Figure 1).