A Real Time Adaptive Charging Approach for Cycle Life Extension of Li Ion Cells

Abstract

It is commonly understood that preservation of Lithium-ion battery life comes at the expense of charge time. In this manuscript a novel real time charging framework has been developed that charges the battery in a time as fast as the constant current-constant voltage (CC-CV) protocol while ensuring minimum loss of cycle life. The framework consists of a reduced order electrochemical model integrated with an optimization routine. The charge profile adapts to the battery state of charge and health in real time and is amenable for on-device implementation. Cycle life benefits of the novel adaptive charging profile are compared with traditional CC-CV charging of commercial Lithium-ion batteries cycled until end of life. In addition to the running capacity, battery health is also compared at a low probe C-rate(C/5) to assess the benefits in minimizing irreversible losses. A differential voltage analysis of Probe (C/5 rate) reveals that adaptive charging is able to eliminate the loss of active material (LAM) that is seen typically at advanced cycles. The framework is implemented on a mobile device and shows a substantial benefit in battery life without any penalty on the charge time.