Analysis Of Output Performance Influence And Research On Monitoring Method Of Membrane Water Content For PEMFC Stack

Proton Exchange Membrane Fuel Cell(PEMFC) is the most suitable for people in daily life among the fuel cells, because of its high power density, no pollution and low temperature starting. However, in practice, the output performance of PEMFC stack is greatly influenced by the operating conditions(temperature,humidity, etc). Studying the effects of operating conditions on the output performance of PEMFC stack can realize an effective control of operating conditions.Meanwhile, The PEMFC Stack’s membrane water content change is difficult to accurately monitor while the monitoring methods for membrane water content will achieve good water management, achieving the goal of optimal output performance.This article starts from the fuel cell stack’s working characteristics, studying the influence of operating conditions on output performance of PEMFC, combining with the characteristics of V-I and impedance. Then proposed a new and rapid electrochemical impedance spectroscopy(EIS) method to detect water content of the membrane. The main research contents are as follows:1. Theory analysis and simulation research. Combining the PEMFCS’s structure and reaction characteristics, analyze influence factor of the output performance of PEMFC, obtaining the theoretical V-I relationship, and put forward the V-I parameters for simplifying the expressions. Then use the MATLAB simulation analysis the specific change law come from the effects of operating conditions on the output properties. Finally, establish the equivalent circuit model of PEMFC.2. Building the experimental platform and experimental method. In order to achieve the study, design and build the water-cooling PEMFC stack experiment platform and PC monitoring software. According to the activation, ohms and concentration polarization of the stack, characteristics of V-I and EIS experiments were conducted in variety of different operating conditions.3. Data analysis and experimental methods proposed. Through the analysis ofthe V-I curve variation under different operating conditions and the impedance parameter of fitting, the output performance optimization method of PEMFC stack is obtained, while obtaining the influence of operating conditions on the V-I parameters. Finally, based on the experiment results, put forward a method based on F-EIS that can detect the membrane water content, then verify its effectiveness from experiment, which has a great help to the actual control and application of PEMFC.