Effect of Relaxation Periods over Cycling Performance of a Li-Ion Battery. Issue 2 (1st January 2015)

• Record Type: Journal Article
• Authors: Rashid, Muhammad; Gupta, Amit
• Is Part Of: Journal of the Electrochemical Society. Volume 162:Issue 2(2015)
• Page Start: A3145
• Page End: A3153
• Publication Date: 2015-01-01
• Subjects: Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0201502jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : Various operational parameters such as charge/discharge rates, relaxation periods, and depth of charge and discharge play an important role in enhancing the cycling life of Li-ion batteries. Providing batteries with a relaxation period after discharging and charging might be essential for removing concentration gradients generated due to passage of current. In the present work, the effect of providing open-circuit time durations after completion of each charge and discharge over the performance of Li-ion cells has been analyzed and quantified. It is shown that relaxing the cell after discharge has significant influence over cell performance, whereas relaxation after charge has a marginal effect. In the former case, a relatively thicker film forms at the solid-electrolyte interface in the negative electrode. Moreover, providing a sufficiently long relaxation to the cell at the end of discharge results in (a) a higher concentration of lithium in the solid matrix of the negative electrode and (b) a lower concentration of lithium in the positive electrode, both leading to a higher cell potential during the discharge phase of the subsequent cycle. Charging the cell following a relaxation period of more than one hour at the end of discharge results in a better utilization of cyclable lithium.