Pathways towards managing cost and degradation risk of fast charging cells with electrical and thermal controls

The charging rate of Li-ion batteries is limited by the risks of lithium plating and thermal damage, both of which negatively affect lifetime of the batteries. This work analyzes how to minimize charge time and manage the risk of degradation using both electrical and thermal controls. To accomplish this, an electrochemical-thermal model is developed to introduce a constant-risk fast charging protocol which maximizes the charging current while maintaining the cell within pre-defined design limits selected to minimize the risk of degradation. Results indicate 80%-charging of a typical NMC/graphite cell can be achieved within 10 minutes with a cell cost under $100 kW(-1) h(-1) (corresponding to an 80 mu m thick anode) when charged at moderate allowable risks of degradation. We also demonstrate how stretching the allowable risk (i.e., higher temperatures, larger C-rates, and lower anode potential limits) allows affordable design of fast charging cells.