Cho, Kyu Taek
M.S. (Master of Science)
Department of Mechanical Engineering
The aluminum-air battery is a very promising electrical energy storage system for portable electronics and electric vehicles because it is safe, inexpensive, and has a very high energy density. With the [EMIm]Cl-AlCl3 room-temperature ionic liquid (RTIL) electrolyte, by controlling the acidity, H2 evolution and dendrite formation are prevented and the Al2O3 passive film on the anode can be partially dissolved (cracked), so the battery’s lifespan is extended and even allows battery charging. Still, the Al2O3 passive film on the anode and Al2O3 deposition on the cathode remain issues which negatively affect battery performance. While these phenomena have been experimentally observed, it is difficult to understand the underlying physics and define key parameters that affect performance from experimentation alone.
In this research, a 1D, physics-based mathematical model of an Al-air battery with 1:1.5 [EMIm]Cl-AlCl3 electrolyte was developed in COMSOL Multiphysics. The model consists of the anode surface, a porous (cracked) Al2O3 layer on the anode surface, a porous separator, and a porous carbon cathode. To account for the complexities of porous media, the model is governed by volume-averaged macroscopic equations, which are used to analyze the multiphysics electrochemical reactions.
The model was first validated by comparing galvanostatic discharge performance curves with existing experimental data. Four parametric studies were conducted by adjusting the anode’s Al2O3 film porosity, solubility of oxygen into the cathode, cathode porosity, and cathode thickness. Each test showed a relation between raising the parameter and significantly better battery performance. Cathode design parameters for optimal performance are provided in this thesis. As it is the first mathematical modeling analysis of an Al-air battery, the results from this research are valuable information that may be used for future research and development of Al-air batteries.
Welch, Christopher Charles, "Micro-macro Mathematical Modeling Analysis of an Al-Air Battery" (2020). Graduate Research Theses & Dissertations. 7771.
Northern Illinois University
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