Degradation Differences of a Single Proton Exchange Membrane Fuel Cell: Energy Management Strategy and Dynamic Programming

摘要

The durability of proton exchange membrane fuel cells (PEMFC) is one of the limitations to its wide application in vehicles and other equipment. In this paper, a running profile of PEMFC using dynamic programming (DP) energy management strategy (EMS) is designed. The degradation of a single PEMFC is studied by running a single PEMFC under the designed cycle. Voltage decline rate reaches 1240 μV/h at 600 mA/cm2 /s, faster than most Acceleration Stress Tests (AST). Performance decline difference in different areas of a single PEMFC is investigated. Degradation differences in 6 regions are analyzed using Localized Electrochemical Impedance Spectroscopy (EIS). The results show that the gas inlet area has higher and increasing high frequency resistance (HFR). Degradation of proton transport of proton exchange membrane (PEM) is related to hydrogen concentration and water content in the membrane. Gas inlet regions are less affected by mass transfer. This may due to less water being produced and accumulated near the gas inlet. Deterioration of mass transfer is related to corrosion of reactants/products micro channels that damage drainage capacity. Accumulated water blocks the transportation of reactants and causes flooding phenomenon. Charge transfer resistance also increases, indicating that catalyst layers also suffer during the durability experiments.