Evaluation the Resistance Growth of Aged Vehicular Proton Exchange Membrane Fuel Cell Stack by Distribution of Relaxation Times

Abstract

The aged stack results in resistance growth and power decline. At present, most of the analyses of resistance growth are qualitative or identified by complex mechanism models. For more effective identification, the distribution of relaxation times (DRT) method is applied to the aging analysis of the stack. The individual polarization process of the stack corresponding to each DRT peak is determined by appropriate experimental conditions and the impedance of the individual polarization process is characterized by the peak area. The three DRT peaks from low frequency to high frequency are identified as the mass transport, the charge transfer of oxygen reduction reactions (ORRs), and the proton transport in the cathode catalyst layer (CCL) and anode side. The stack’s voltage recession rate is 15% at the rated current density of 800 mA cm−2 after running for 2000 h in the driving cycle. Mass transport is the main reason accounting for 66.1% of the resistance growth. The charge transfer resistance growth cannot be ignored, accounting for 30.23%. The resistance growth obtained by the DRT can quickly and accurately identify the main reason for stack decline and therefore promises to become an important diagnostic tool in relation to aging.

pH and pCl Operational Parameters in Some Metallic Ions Separation with Composite Chitosan/Sulfonated Polyether Ether Ketone/Polypropylene Hollow Fibers Membranes

“…The FTIR spectra revealed, for each constituent of the composite membrane (Chi/sPEEK/PPHF), characteristic absorption bands; for sPEEK (Figure 7b)), one can observe the peak at 1656 cm −1 (as a small shoulder) assigned to the stretching mode of C=O, and the indicative peaks for the presence of O=S=O groups at 1223, 1078, and 1019 cm −1 . The sharp peak at 1592 cm −1 (C=C) had a reduced intensity and this feature is attributed to the crosslinking of the sPEEK chains with oxygen, as described in the literature [75][76][77][78]. The PPHF FTIR-ATR spectrum (Figure 7a) showed peaks centered at 2955, 2920, 2866, and 2843 cm −1 , very characteristic features of stretching vibration modes of -CH 2 -, -CH-, and -CH 3 groups from polypropylene material.…”

“…These characteristics are useful to the experimenter that will be able to effortlessly select the fibers needed to enter the specific permeation module. UV-Vis spectrometry examination may also be an indicator of membrane aging [78].…”

“…These characteristics are useful to the experimenter that will be able to effortlessly select the fibers needed to enter the specific permeation module. UV-Vis spectrometry examination may also be an indicator of membrane aging [78]. These characteristics are useful to the experimenter that will be able to effortlessly select the fibers needed to enter the specific permeation module.…”

The Operating Parameters, Structural Composition, and Fuel Sustainability Aspects of PEM Fuel Cells: A Mini Review

“…The PEMFC operates at a temperature range from 60 to 85 • C for low-temperature PEMFC (LT-PEMFC), on the other hand, the temperature operation range varies from 120 to 140 • C in the case of high-temperature PEMFC (HT-PEMFC), with an average power capacity of ≤120 kW and electrical efficiency of 50-60% [19]. Nevertheless, PEMFC technology still faces several technical and economic challenges, which are related to the cost of catalysts, operating temperature conditions, durability/stability [20], the infrastructure of membrane electrode assembly (MEA) corrosion [21], and water management problems [22][23][24].…”

A Study of Contact Pressure with Thermo-Mechanical Coupled Action for a Full-Dimensional PEMFC Stack

“…In the automotive sector, there is a growing need for research on the optimization of fuel cell stack performance. Although the field of PEMFC stack performance optimization is quite broad, the contact pressure on the multi-contact interface between the BPP and MEA must be especially well-controlled, since it greatly influences the electron transportation and fuel supply [9,10], thereby affecting the output characteristics [11].…”