Performance Conversion Rate of Proton Exchange Membrane Fuel Cells

Proton exchange membrane fuel cell (PEMFC) is one of a kind high efficiency with hydrogen acts as a reducing agent and oxygen (air) acts as an oxidant a clean electrochemical power generation device that can directly convert the chemical energy of the fuel into electricity and is not limited by the Karnot cycle effect, so it has a high energy conversion rate (40%-60%). PEMFC units do not contain mechanical motion elements, so they work reliably, require less maintenance, and operate quietly and quietly. The influencing factors limiting the performance conversion rate of PEMFC are mainly: activation polarization, ohmic polarization, and concentration polarization. First, activation polarization: The main factor affecting the FC voltage in the low current density region is activation polarization. The activation polarization phenomenon is mainly due to the wonder of the electrode electrochemical reaction delay caused by its potential deviation from the equilibrium potential. Second, ohmic polarization: As the current density increases, ohmic polarization loss gradually dominates. This is mainly due to the voltage loss caused by the current collector plate, the contact resistance between the membrane electrode assemblies, etc. Third, the concentration difference polarization: when the current density reaches a specific value, the gas concentration polarization will cause the voltage to drop sharply, and the current value reaches the current limit density. Therefore, the transport efficiency of the reactant gas in the high current density region is an important factor affecting the fuel cell, and the flow channel layout is the key to affecting the reactant gas and the active area of the cell, improving the diffusion efficiency of the reactant gas and enhancing the drainage performance of the cell.