Impact of constant and pulsed active balancing current patterns on the aging of lithium-ion batteries

Lithium-ion batteries (LIB) have been widely used in electric vehicles for the past decade because of their advantageous properties, such as low self-discharge, high power and energy density, long life, wide operating temperature range, and lack of memory effect. However, the available energy and power deteriorate because of inconsistent operations caused by various external factors. For stable operation, it is crucial to focus on the accurate assessment of the state of health (SOH) of LIB, which is a challenging task. This article presents an investigation of the effect of different current patterns (constant- and pulsed-current discharge) on battery performance. Constant current (CC) and pulsed current (PC) cycles were used to represent possible current battery patterns to be used during active cell balancing. This analysis was conducted using a simple and costeffective method that aims to measure the battery capacity directly by integrating current over time. The findings indicate higher capacity retention and lower thermal stress when the LIB is cycled under PC discharge than under CC discharge. To thoroughly explore the effects of both current patterns, a comparative analysis of the capacity fade and change in internal resistance is considered. Compared with CC discharge, the capacity fade and power loss due to increase in resistance were relatively improved by 2 % and 8.7 %, respectively, under PC discharge. These results show that PC is preferable in active balancing solutions to preserve the LIB lifetime and performance.