Decay mechanism and capacity prediction of lithium-ion batteries under low-temperature near-adiabatic condition

Lithium batteries are affected by low temperatures during use leading to performance degradation. In order to achieve a diagnosis of the degradation mechanism of lithium batteries at low temperatures while completing capacity predictions, the following work is done: first, the effects of low temperatures and near-adiabatic conditions on lithium batteries are explored. Secondly, a quantitative analysis of the degradation patterns in terms of capacity, incremental capacity (IC), differential voltage (DV) and electrochemical impedance spectroscopy (EIS) showed that loss of active matter (LAM) and lithium ion loss (LLI) were the main causes of degradation in lithium batteries, in addition to the loss of conductivity (CL), which was three times higher at low temperatures than at room temperature. The battery is then disassembled to further analyse the effects of low temperature and near-adiabatic conditions on the lithium battery from an internal mechanistic perspective; Finally, the quantified results were fed into a CNN-LSTM prediction model to achieve the capacity prediction of lithium batteries at low temperatures with an average error of 1.19% and 4.66% respectively. This study provides a basis for diagnosing the aging mechanism and predicting the capacity of Li-ion batteries at low temperatures, which will help manufacturers to improve battery design and battery management system (BMS) strategies to extend battery life in cold regions.