Membrane Electrolyte Assembly Health Estimation Method for Proton Exchange Membrane Fuel Cells

Abstract

Membrane electrolyte assembly (MEA) aging is a major concern for deployed proton exchange membrane (PEM) fuel cell stacks. Studies have shown that working conditions, such as the operating temperature, humidity, and open circuit voltage (OCV), have a major effect on degradation rates and also vary significantly from cell to cell. Individual cell health estimations would be very beneficial to maintenance and control schemes. Ideally, estimations would occur in response to the applied load to avoid service interruptions. To this end, this paper presents the use of an extended Kalman filter (EKF) to estimate the effective membrane surface area (EMSA) of each cell using cell voltage measurements taken during operation. The EKF method has a low computational cost and can be applied in real time to estimate the EMSA of each cell in the stack. This yields quantifiable data regarding cell degradation. The EKF algorithm was applied to experimental data taken on a 23-cell stack. The load profiles for the experiments were based on the FTP-75 and highway fuel economy test (HWFET) standard drive cycle tests to test the ability of the algorithm to perform in realistic load scenarios. To confirm the results of the EKF method, low performing cells and an additional “healthy” cell were selected for scanning electron microscope (SEM) analysis. The images taken of the cells confirm that the EKF accurately identified problematic cells in the stack. The results of this study could be used to formulate online sate of health estimators for each cell in the stack that can operate during normal operation.

Potential of sodium alginate/titanium oxide biomembrane nanocomposite in DMFC application

“…In addition, high efficiency in the process of energy conversion as well as non-combustion processes have reduced greenhouse gas emissions causing DMFCs to be interested in addressing environmental issues. [7][8][9][10] Nafion membranes are currently used because of their advantages over other membranes like excellent conductivity of proton, noble chemical, and physical stability. [2][3][4][5][6] The membrane electrolyte assemble is the most important part of the DMFC and consists of electrodes (anodes and cathodes) that function as a centre for reactions and membranes that separate the anode and cathode; the membranes also serve as a barrier to the methanol trajectory as well as a pathway for protons, which are very important conductive agents.…”

“…[2][3][4][5][6] The membrane electrolyte assemble is the most important part of the DMFC and consists of electrodes (anodes and cathodes) that function as a centre for reactions and membranes that separate the anode and cathode; the membranes also serve as a barrier to the methanol trajectory as well as a pathway for protons, which are very important conductive agents. [7][8][9][10] Nafion membranes are currently used because of their advantages over other membranes like excellent conductivity of proton, noble chemical, and physical stability. [11][12][13] Unfortunately, there are major disadvantages that prevent the continued commercialization of Nafion, which are expensive cost production and high crossover of methanol problems, which result in the loss of fuel and potential mixture on the cathode side, thereby reducing DMFC's overall performance.…”