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Polymer Electrolyte Membrane Fuel Cell (PEMFC) is regarded as a potential alternative clean energy source for automobile applications. Key challenges to the acceptance of PEMFC for automobiles are the cost reduction, improvement in power density for its compactness, and cold-start capability. High current density operation is a promising solution for them. However, high current density operation under normal and sub-zero temperature requires more oxygen flux for the electrochemical reaction in the catalyst layer, and it causes more heat and water flux, resulting in the significant voltage losses. So, the theoretical investigation is very helpful for the fundamental understanding of complex transport phenomena in high current density operation under normal and sub-zero temperature. In this study, the numerical model was established to elucidate the impacts of mass transport phenomena on the cell performance through the numerical validation with experimental and visualization results.

Considerable improvements can be obtained in battery performance for hybrid electric vehicles (HEVs) by employing an electrochemistry-transport model based on a multi-physics modeling framework and ultrafast numerical algorithms. One important advantage of this approach over the lumped equivalent circuit (or look-up table) approach is the ability of the former to adapt to changes in design and control. In this work, we present mathematical and numerical details of our approach, and demonstrate the robustness of this battery model in simulation of short-pulse charge/discharge characteristic of HEV driving cycles under room and low temperatures.

A previously validated 1-D electrochemical model of a 72 cell, 6 Ah, 276 V nominal lithium-ion hybrid vehicle battery pack is used to predict maximum discharge current for discharge pulses ranging from zero to twenty seconds in duration from various state of charge (SOC) initial conditions. Ohmic drop from open-circuit potential limits instantaneous pulse power capability (83 kW from 50% SOC) while Li+ diffusion inside negative electrode active material solid particles limits long-time capability (28 kW for a 20 second pulse from 50% SOC). A simple lumped negative electrode solid diffusion model is derived to dynamically describe electrode-averaged solid phase concentration distribution inside of active material particles as a function of measured current time history.