TY  - JOUR
A1  - Schopen, Oliver
A1  - Shah, Neel
A1  - Esch, Thomas
A1  - Shabani, Bahman
T1  - Critical quantitative evaluation of integrated health management methods for fuel cell applications
JF  - International Journal of Hydrogen Energy
N2  - Online fault diagnostics is a crucial consideration for fuel cell systems, particularly in mobile applications, to limit downtime and degradation, and to increase lifetime. Guided by a critical literature review, in this paper an overview of Health management systems classified in a scheme is presented, introducing commonly utilised methods to diagnose FCs in various applications. In this novel scheme, various Health management system methods are summarised and structured to provide an overview of existing systems including their associated tools. These systems are classified into four categories mainly focused on model-based and non-model-based systems. The individual methods are critically discussed when used individually or combined aimed at further understanding their functionality and suitability in different applications. Additionally, a tool is introduced to evaluate methods from each category based on the scheme presented. This tool applies the technique of matrix evaluation utilising several key parameters to identify the most appropriate methods for a given application. Based on this evaluation, the most suitable methods for each specific application are combined to build an integrated Health management system.
KW  - Fuel cell
KW  - Health management system
KW  - Online diagnostic
KW  - Fault detection
KW  - Non-model-based Evaluation
Y1  - 2024
U6  - https://doi.org/10.1016/j.ijhydene.2024.05.156
SN  - 0360-3199
VL  - 70
SP  - 370
EP  - 388
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Schopen, Oliver
A1  - Narayan, Sriram
A1  - Beckmann, Marvin
A1  - Najmi, Aezid-Ul-Hassan
A1  - Esch, Thomas
A1  - Shabani, Bahman
T1  - An EIS approach to quantify the effects of inlet air relative humidity on the performance of proton exchange membrane fuel cells: a pathway to developing a novel fault diagnostic method
JF  - International Journal of Hydrogen Energy
N2  - In this work, the effect of low air relative humidity on the operation of a polymer electrolyte membrane fuel cell is investigated. An innovative method through performing in situ electrochemical impedance spectroscopy is utilised to quantify the effect of inlet air relative humidity at the cathode side on internal ionic resistances and output voltage of the fuel cell. In addition, algorithms are developed to analyse the electrochemical characteristics of the fuel cell. For the specific fuel cell stack used in this study, the membrane resistance drops by over 39 % and the cathode side charge transfer resistance decreases by 23 % after increasing the humidity from 30 % to 85 %, while the results of static operation also show an increase of ∼2.2 % in the voltage output after increasing the relative humidity from 30 % to 85 %. In dynamic operation, visible drying effects occur at < 50 % relative humidity, whereby the increase of the air side stoichiometry increases the drying effects. Furthermore, other parameters, such as hydrogen humidification, internal stack structure, and operating parameters like stoichiometry, pressure, and temperature affect the overall water balance. Therefore, the optimal humidification range must be determined by considering all these parameters to maximise the fuel cell performance and durability. The results of this study are used to develop a health management system to ensure sufficient humidification by continuously monitoring the fuel cell polarisation data and electrochemical impedance spectroscopy indicators.
KW  - PEM fuel cell
KW  - Electrochemical impedance spectroscopy
KW  - Relative air humidity
KW  - Active humidity control
KW  - Impedance analysis
Y1  - 2024
SN  - 0360-3199 (print)
U6  - https://doi.org/10.1016/j.ijhydene.2024.01.218
SN  - 1879-3487 (online)
VL  - 58
IS  - 8
SP  - 1302
EP  - 1315
PB  - Elsevier
CY  - Amsterdam
ER  -