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Abhishek Sarkar1 Abhijit Chandra1 Pranav Shrotriya1

1, Iowa State University, Ames, Iowa, United States

In the advent of fast charging and high voltage storage devices, thermal runaway followed by meltdown of lithium ion battery is a cause of concern. Prior experiments on lithium battery modules have shown issues of high thermal generation in high energy storage electrodes. Theoretical and numerical analysis have focused on either the factors causing heat generation from electrode particles at microscale or the possible thermal management techniques to mitigate thermal failure in fullscale battery. We report a multiscale thermomechanical model which bridges heat generation by the electrode particle to thermal runaway in a multilayered electrode separator system. The thermal analysis is coupled with an elasto-plastic diffusion induced stress model to compare the thermal and mechanical performance under different design and operating parameters. A parametric analysis is performed for combination between three cathode and anode materials and the performance of the model is studied over a range of particle radius and charging rates. Higher charging rate and larger particle size are found to push the electrode into plastic deformation. Four modes of heat generation are considered including three conventional heating modes, i.e. polarization heating due to surface over-potential, entropic heating due to entropy release during lithiation, resistive heating due to electrical resistivity of the electrodes; and heat generation from the plastic deformation of electrode particles under faster charging condition. The results present a conflicting scenario where reducing the particle size diminishes the stress field but increases the volumetric heat generation, and vice-versa. The paper concludes with a set of optimum design parameters and limiting charging rate for different electrode material combinations in a battery and proposes thermal management techniques to permit faster charging of the battery.

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