Study on the discharge behavior of spent lithium-ion batteries under externally assisted conditions

Abstract

The lithium-ion batteries (LIBs) market continues to expand with the global energy mix transition and the electrification of transportation. Due to limitations in service life and complex operating conditions, a large number of spent LIBs have been generated. Unpredictable residual charge may exist in spent LIBs, which can lead to potential threats such as short circuits, fires, and even explosions during transportation, storage, and disposal. Discharge treatment can release the residual charge in spent LIBs and reduce safety risks. In this paper, chemical methods were employed to discharge spent LIBs, and the effects of different solution systems and solution concentrations on the discharge behavior are investigated. In addition, the influence and mechanism of changes in external parameters of the solvent system (magnetic stirring, ultrasonic oscillation) on the discharge behavior are also studied. The discharge time of spent LIBs in the used solutions is in the order of NaNO₃ > LiCl > Na₂SO₄ > NaCl > FeSO₄ at the same concentration. The time required for complete discharge under magnetic stirring and ultrasonic oscillation conditions was 60 minutes and 40 minutes, respectively. This study can provide a reference for the discharge of spent LIBs in solution.