Implementation of DEIS for reliable fault monitoring and detection in PEMFC single cells and stacks

Darowicki, Kazimierz; Janicka, Ewa; Mielniczek, Michal; Zieliński, A.; Gawel, L.; Mitzel, Jens; Hunger, Jürgen

doi:10.1016/j.electacta.2018.09.105

Cited by 26 publications

(9 citation statements)

References 49 publications

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“…On the same impedance graph for low-current loads, the instantaneous impedance spectra are also significantly shifted toward positive values of the real impedance part, which indicates greater electrolyte resistance; however, to obtain information on the processes determining the fuel cell operation, an in-depth impedance analysis is necessary. For this purpose, the equivalent circuit shown in Figure 4 was used, the selection and validation of which was described by the authors in a previous study [39]. Changes in the instantaneous values of the equivalent circuit elements in the function of current for different RH values of the reaction gases are presented in Figures 5-10.…”

Section: Resultsmentioning

confidence: 99%

“…Due to the introduction of an additional variable component in the current signal, it is possible to simultaneously monitor the voltage and instantaneous impedance spectra during the variable load of the fuel cells. The DEIS method has been successfully used to identify malfunctioning cells in fuel cell stacks [39,40] and also for selecting the optimal conditions of the fuel cell operation [41,42].…”

Section: Introductionmentioning

confidence: 99%

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Optimization of the Relative Humidity of Reactant Gases in Hydrogen Fuel Cells Using Dynamic Impedance Measurements

et al. 2021

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Water management is a key factor affecting the efficiency of proton exchange membrane fuel cells (PEMFCs). The currently used monitoring methods of PEMFCs provide limited information about which processes or components that humidity has a significant impact upon. Herein, we propose the use of a novel approach of impedance measurements using a multi-sinusoidal perturbation signal, which enables impedance measurements under dynamic operating conditions. The manuscript presents the effect of the relative humidity (RH) of the reactants on the instantaneous impedance of the middle cell in the PEMFC stack as a function of the current load. Analysis of changes in the values of equivalent circuit elements was carried out to determine which process determines the stack’s performance depending on the load range of the fuel cell during operation. Comprehensive impedance analysis showed that to ensure optimal cell operation, the humidity of the reactants should be adjusted depending on the load level. The results showed that at low-current loads, the humidity of gases should be at least 50%, while at high-current loads, the cell should operate optimally at a gas humidity of 30% or lower. The presented methodology provides an important tool for optimizing and monitoring the operation of fuel cells.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimization of the Relative Humidity of Reactant Gases in Hydrogen Fuel Cells Using Dynamic Impedance Measurements

et al. 2021

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“…EIS allows the differentiation between nominal operation and operation under critical conditions, such as flooding, dryout or reactant starvation [37,38]. Furthermore, EIS devices using multiple, parallel channels can be used to identify inhomogeneous operation of individual cells.…”

Section: Impedance Setupmentioning

confidence: 99%

Fault Diagnostics in PEMFC Stacks by Evaluation of Local Performance and Cell Impedance Analysis

et al. 2020

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Starvation, flooding, and dry‐out phenomena occur in polymer electrolyte membrane fuel cells (PEMFCs), due to heterogeneous local conditions, material inhomogeneity, and uneven flow distribution across the single cell active area and in between the individual cells. The impact of the load level and air feed conditions on the performance was identified for individual single cells within a 10‐cell stack. Analysis of the current density distribution across the active area at the cell level was correlated with electrochemical impedance spectroscopy to enable operando fault diagnostic without any impact of the applied analytical tools on the single cell behavior. Moreover, the combination of both technologies allows in‐depth analysis of fault mechanisms in fuel cell single cells with improved sensitivity. Current density distribution and the quantitative assessment of the performance homogeneity demonstrated high sensitivity to small humidity changes and allow the detection of critical events, such as dry‐out in single cells. Impedance analysis is more sensitive regarding polarization and diffusion limitations and allows detection of cell flooding. The combination of both techniques is required for reliable identification of air starvation faults.

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“…Various electroanalytical methods used to study classical laboratory electrode systems have been adapted for studying PEMFC stacks [12,13]. The portfolio of electrochemical methods currently available for stacks includes current interrupt (internal cell resistance measurement) [14,15], voltammetry (real electrochemically active electrode area measurement, electrocatalyst chemistry assessment, determination of electronic shorting in MEAs, fuel crossover measurement) [16,17], stripping voltammetry (real electrochemically active electrode area measurement, electrocatalyst chemistry assessment) [18], potentiometry (as in voltammetry) [19][20][21], amperometry (fuel crossover measurement) [17,22], and electrochemical impedance spectroscopy (EIS, quantification of different sources of stack polarization under load, structural information about electrodes) [23,24]. These methods have been developed for hydrogen-fueled (H 2 -PEMFC) as well as methanol-fueled (DMFC) stacks [18,[25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Looking Inside Polymer Electrolyte Membrane Fuel Cell Stack Using Tailored Electrochemical Methods

Piela

Mitzel

Rosini

et al. 2020

Journal of Electrochemical Energy Conversion and Storage

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Voltammetry, potentiometry, amperometry, and electrochemical impedance spectroscopy (EIS) were used to study practical polymer electrolyte membrane fuel cell (PEMFC) stacks in an attempt to validate the stack-tailored electrochemical methods and to show the range of information about a PEMFC stack obtainable with the methods. In-stack electrode voltammetry allowed to determine the type, i.e., the surface chemistry, of catalysts used to make the stack electrodes and to measure the electrodes’ true active surface areas (EASAs). Stack potentiometry gave the EASAs, too, but only after calibration of the method against voltammetry. The speed of the test is the advantage of the stack potentiometry. An amperometry-based protocol was introduced to measure the hydrogen permeability and electronic shorting of the stack membrane-electrode assemblies. Dependence of the H2 permeability on H2 pressure and the stack temperature was shown. EIS in the hydrogen-pump mode was used to study the anode and electrolyte membrane processes under load. Spectra were dominated by humidification effects, which allowed probing the external humidification distribution to the anodes in the stack. Cathode EIS spectra obtained by subtraction of H2-H2-mode spectra from H2-air-mode spectra were modeled and the ohmic, charge-transfer, and oxygen mass-transport contributions to the stack polarization under load were separated. The variability of these contributions across the stack was discussed.

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Implementation of DEIS for reliable fault monitoring and detection in PEMFC single cells and stacks

Cited by 26 publications

References 49 publications

Optimization of the Relative Humidity of Reactant Gases in Hydrogen Fuel Cells Using Dynamic Impedance Measurements

Optimization of the Relative Humidity of Reactant Gases in Hydrogen Fuel Cells Using Dynamic Impedance Measurements

Fault Diagnostics in PEMFC Stacks by Evaluation of Local Performance and Cell Impedance Analysis

Looking Inside Polymer Electrolyte Membrane Fuel Cell Stack Using Tailored Electrochemical Methods

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