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

Abstract

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.

Advancement of Segmented Cell Technology in Low Temperature Hydrogen Technologies

“…The advantageous use of this monitoring technology for cathodic fault monitoring was demonstrated in a stationary fuel cell stack of ten cells, equipped with three segmented cells, which were placed at both ends and in the centre of the stack, as indicated in Figure 9. The stack was accompanied by an electrochemical impedance spectroscopy (EIS) setup, with the purpose to correlate the findings from both techniques [85]. While EIS data are typically strongly depending on the underlying model used for interpretation and thus not always clearly readable, the correlation supports the interpretation of both methods.…”

Neural Network based Diagnostic of PEM Fuel Cell

“…the Nernst potential in series with some resistances representing the voltage drops. Also, the fluid dynamics have been taken into account through using equations (16)(17)(18)(19), involving the partial pressure of hydrogen (respective oxygen) and the flow of hydrogen entering the cell (respective oxygen).…”

“…Among the most used methods for characterization is electrochemical impedance spectroscopy (EIS). This method is employed to measure the value of the electrical resistance or for monitoring degradation [14][15][16][17][18]. During each degradation phase, EIS can be carried out to characterize the impedance and describe its evolution of the parameters in order to allow differencing between drying and flooding.…”

Experimental investigation of stable the proton exchange membrane fuel cell control using magnetic sensor probes

“…However, these operations can cause dry-out. Therefore, for monitoring this failure, methods including cell segmentation [10], temperature measurement [11,12], cell resistance (through current interrupt) [13][14][15], and cell impedance (through the Cole-Cole plot) [10,[15][16][17], and MRI [6] are utilized. As these results affect the strategies for mitigating dry-out such as control of the operating flow rate [18] and temperature [19], it is crucial to prevent such main failures, which affect the cell performance in a PEMFC system.…”