An Experimental Study of Scale-up, Oxidant, and Response Characteristics in PEM Fuel Cells

It is important for fuel cell to become flexible in order to accommodate the situations of application areas for reducing costs and expanding coverage. Scale ups in series and parallel to 1-kW class proton exchange membrane (PEM) fuel cell stack are characterized experimentally with oxidant as air and oxygen. Through a serial scaled-up 4-cell stack with an active area of 25 cm² and a parallel scaled-up single cell with an active area of 100 cm², respectively, the 1-kW class 20-cell stack with an active area of 150 cm² per cell is scaled up from the basic unit cell with maintaining their performances. The polarization and power curves of the 1-kW class PEM fuel cell stack with the reactants H₂/air and H₂/O₂ are evaluated. Sufficient power of the PEM fuel cell can operate at flexible nominal current of 40-80 A and nominal voltage of 12-15 V for providing durability and balance between cells. The 1-kW class PEM fuel cell stack is characterized through the comparison of cell voltage differences utilizing H₂/air and H₂/O₂. Both cell voltages with H₂/air and H₂/O₂ follow well the one-twentieth of the responding stack voltages with the small difference.