A Comparison of Internal and External Preheat Methods for NMC Batteries

Lithium-ion batteries (LiBs) performance can be significantly declined when operated at
cold climates in terms of capacity loss, resistance increase and accelerated aging rates. To prevent
this downgrade and to maintain the optimal operation of battery cells, a preheat process is taking
place, which can be implemented either by internal or external techniques. The former is performed
actively, by circulating a constant amplitude and frequency alternative pulse current (APC) at the
battery cell’s terminal and preheating it internally by harvesting its generated Joule losses. The latter
is achieved passively, by enclosing the cell into thermal blankets. In this work, a comparison of these
two preheating strategies is presented, by proposing electro-thermal and lifetime models of a lithium
nickel manganese cobalt oxide (NMC/G) 20 Ah pouch battery cell. Heat transfer, energy efficiencies
and degradation costs are estimated during operation of the preheat techniques. Validation of the
model showed a good agreement between the model and experimental data, and a study case is
proposed to estimate and compare the cost efficiency of the methods as based for an economic study.

Publication year:2019

Accessibility:Open