Multidimensional signal fusion strategy for battery thermal runaway warning towards multiple application scenarios

Owing to the widespread application of lithium-ion batteries (LIBs), various operating conditions pose significant challenges to battery safety. Developing precise and prompt warning strategies is crucial for preventing LIB safety issues in different application scenarios. Herein, the effects of charge rate (C-rate), ambient temperature (A-temp), preload force (P-force), and initial state of charge (I-SOC) on multidimensional signal evolution are comprehensively investigated based on the orthogonal design method. The time sequences of the expansion force, voltage, gas concentration, and temperature during the overcharge abuse tests were discussed in detail, and the quantification of the SOC boundary for these signals was emphasized. Overall, the expansion force is the earliest abnormal signal, which is minimally influenced by the four factors under various operating conditions, and can be used as a warning indicator before venting. During the overcharging process, the SOC boundary corresponding to abnormal expansion force (Fabn), temperature (Tabn), internal short circuit (ISC), and thermal runaway (TR) are within ranges of 106.38–110.92 %, 110.50–164.76 %, 123.17–187.86 %, and 125.71–165.18 %, respectively, which are mainly affected by the C-rate. However, the venting SOC boundary ranging from 111.96 % to 119.45 % is predominantly influenced by A-temp. Additionally, the abnormal voltage (Uabn) SOC boundary ranging from 111.45 % to 117.38 % shows a relatively consistent influence from the four factors. Based on this, a three-level safety warning strategy with a corresponding response action applicable to various operating conditions was proposed under the guidance of multidimensional signal fusion. This study provides essential safety guidance for the wider application of LIBs, contributing to the resolution of storage and utilization issues associated with renewable energy.