Aging Mechanism of Lithium-Ion Batteries after Thermal Management Based on Alternating Current Self-Heating at Low Temperature

Abstract

Thermal runaway is one of the severe challenges associated with the widespread use of Li-ion batteries (LIBs). Low-temperature conditions are a common trigger for thermal runaway in LIBs, leading to serious performance degradation and safety issues, including capacity fade, charging difficulties, reduced efficiency, fire risks, and explosions. A novel rapid self-heating approach, which involves introducing an alternating current (AC) into the battery, has emerged as an effective thermal management strategy to address this issue. Here, a 36Ah pouch-type lithium-ion battery is adopted to perform the self-heating cycles by injecting sinusoidal AC into the battery within a specific frequency of the redox boundary and maximum current limited by the voltage boundary at -10 °C. The cycle performance and aging mechanism of the battery have been investigated. The results showed that the ohmic impedance increased by 0.07 mΩ and capacity decreased by 1.7% after the 340th self-heating process. Three lithium inlay platforms of graphite with different degrees of reduction in the discharge differential capacity (dQ/dV) curve indicated that the main failure modes of capacity loss were the loss of negative active materials and lithium ion inventory.

Keywords: Lithium-ion battery, aging mechanism, self-heating, Thermal management, electrochemical performance