Operational intra-cycle temporal and current mode effects on battery capacity loss

Abstract

As part of an on-going research effort towards developing a comprehensive overview of contributing operational factors to lithium ion battery degradation, new analysis and results are presented here which demonstrate the durational effects of battery charge and discharge operations on cell capacity loss. A set of cell cycling tests with a range of different discharge amplitudes provided data for this analysis which led to an advance on how to quantitatively account for the degradation effects in terms of their temporal duration. A factor accounting for operational duration effects usable as a parameter in battery life models was a key result of this project. An additional set of cell cycling experiments was conducted with the aim of decoupling degradation rates attributable to either the discharge or recharge portion of the complete cycle, and some differences were observed and quantified. • Uniquely patterned battery cycling experiments isolated cell degradation factors. • In particular, variable amplitudes and asymmetric cycle forms were tested. • Functionality obtained for a degradation driver based in operational duration. • Decoupling of discharge and recharge effects on degradation; recharge is costlier. • These cycle patterns relate to duty cycles found in the transportation sector.