Karthikeyan Kumaresan

Thermal Model for a Li-Ion Cell

A thermal model for a lithium-ion cell is presented and used to predict discharge performance at different operating temperatures. The results from the simulations are compared to experimental data obtained from lithium-ion pouch cells. The model includes a set of parameters (and their concentration and temperature dependencies) that has been obtained for a lithium-ion cell composed of a mesocarbon microbead anode, LiCoO 2 cathode in 1 M LiPF 6 salt, in a mixture of ethylene carbonate, propylene carbonate, ethyl-methyl carbonate, and diethyl carbonate electrolyte. The parameter set was obtained by comparing the model predictions to the experimental discharge profiles obtained at various temperatures and rates. The concentration and temperature dependence of the extracted parameters were correlated through empirical expressions. Also, the effect of including the thermal dependence of various parameters in the model on the simulated discharge profiles is discussed.

A Mathematical Model for a Lithium–Sulfur Cell

A mathematical model is presented for a complete lithium-sulfur cell. The model includes various electrochemical and chemical (precipitation) reactions, multicomponent transport phenomena in the electrolyte, and the charge transfer within and between solid and liquid phases. A change in the porosity of the porous cathode and separator due to precipitation reactions is also included in the model. The model is used to explain the physical reasons for the two-stage discharge profiles that are typically obtained for lithium-sulfur cells.

Parameter Estimation and Life Modeling of Lithium-Ion Cells

The lithium-ion cell is among the most popular candidates considered actively as a replacement for nickel-based batteries in automobile, small-electronics, satellite, and several other applications. This demand has fueled the need for improved performance and safety of the lithium-ion system. Consequently, a substantial amount of work has gone into understanding the mechanism of the capacity fade occurring in the battery experimentally and via rigorous theoretical analysis. 1-18