A comparative study of the electro-thermal behaviour of the high energy density lithium-ion pouch battery cell and mini module

In this paper, electro-thermal behaviour of a Li-ion pouch cell have been analysed using developed mathematical model, MSMD-based NTGK and ECM models, and the results compared with experiments. The variations of electro-thermal parameters change under CC discharge and WLTP current profile were investigated. Cell terminal voltage at 1 C-rate discharge can be predicted until the last stage of the discharge process with relative errors less than 1.5 %, 2.0 % and 3.0 % for ECM, NTGK and mathematical models, respectively. The maximum relative error in the variation of terminal voltage for the dynamic current profile is 1.5 %, 2.0 % and 2.5 %, respectively. Consequently, ECM model is more successful in analysing battery behaviour. However, mathematical model has a significant advantage over other models due to the analysis time of a few minutes. The methodology implemented in the single-cell models is applicable at the module level. However, the cells within the module are under pressure. A methodology for mini-module assembly has been developed to investigate the effect of compression on electrothermal properties. Mini-module tests showed that the energy provided by the cells under compression increased by 25 % compared to the single cell. Consequently, it is essential to consider compression and other effects in module-level analyses.