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Resistance analysis of PEMFC
Polymer electrolyte membrane fuel cells (PEMFCs) have emerged as a key technology in hydrogen-based clean energy systems. However, achieving high power output and long-term durability requires a precise understanding of internal resistance mechanisms. As a multi-physics system, PEMFCs are influenced not only by electrochemical reactions but also by complex thermal and mass transport resistances. Since these phenomena cannot be explained by a single mechanism, a comprehensive and systematic analytical approach is essential.
We employ distribution of relaxation time (DRT) analysis based on electrochemical impedance spectroscopy (EIS) to quantitatively decompose the internal resistances of PEMFC into mass transport, charge transfer, and proton transport resistances. In particular, mass transport resistance, a major contributor to performance loss, is further dissected using the catalyst agglomerate model and oxygen transport resistance decomposition method. This allows for detailed analysis into molecular diffusion, Knudsen diffusion, and ionomer film resistance. This resistance decomposition approach enables deeper insight into the internal characteristics of PEMFCs, facilitating more effective analysis and optimization.
 - Schematic of the complex resistance analysis methodology
Characteristic of water transport
In PEMFCs, maintaining proper membrane hydration is essential, as insufficient water reduces proton conductivity, while excessive water causes flooding and oxygen starvation. Effective water management, achieved by balancing electro-osmotic drag and back-diffusion, is critical for stable performance and durability.
We focus on key transport properties in polymer electrolyte membranes, including the water diffusion coefficient (Dw), electro-osmotic drag (EOD) coefficient, and ionic conductivity, all of which are characterized as functions of membrane water content and temperature. These parameters are quantitatively evaluated using dynamic vapor sorption (DVS), a new dual-mode sorption model, and hydrogen pumping techniques under both one-way and two-way configurations. We also examine the contributions of the membrane, catalyst layer, and gas diffusion layer to overall water transport, and evaluate ionic conductivity using electrochemical impedance spectroscopy (EIS). This research supports improved PEMFC modeling and contributes to the design of reliable, high-performance fuel cell systems.
 - Schematic of the mechanisms for measuring water transport properties
Development of a dynamic model for PEMFC
PEMFCs technology is leading the way in clean mobility, offering high power density with zero emissions. To meet the demands of automotive applications, PEMFC systems must perform reliably under rapidly changing load conditions. Accurately modeling this dynamic behavior is essential for improving efficiency, durability, and system integration.
We develop a computational model that simulates both steady-state and transient PEMFC operations using MATLAB/Simulink. The model adopts a quasi-three-dimensional approach with a simplified geometric structure, providing an optimal balance between computational efficiency and predictive accuracy. It enables detailed analysis of critical internal processes, such as water management and reactant distribution, which are challenging to observe experimentally. Building on this foundation, we have further advanced the dynamic PEMFC model to scale from single-cell analysis to full-stack performance evaluation. This modeling framework offers valuable insights for real-time performance prediction, control strategy development, and seamless integration into fuel cell-powered vehicle systems.
 - Schematic diagram of the single-cell PEMFC model
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