A novel Al Cu internal short circuit detection method for lithium-ion batteries based on on-board signal processing

Spontaneous battery internal short circuit (ISC) is recognized as a major cause of lithium-ion batteries thermal runaway (TR). Multiple ISC detection methods have been developed to guarantee the secure application of lithium-ion batteries. However, conventional methods are invalid for the AlCu ISC, a distinctive case in all the possible ISC scenarios, because the voltage sampling frequency of battery management system (BMS) is insufficient to detect its transient voltage drop-recovery signals. Considering the difficulty in increasing the voltage sampling frequency of the BMS, a novel on-board AlCu ISC detection method free from dependence on voltage sampling frequency is proposed in this paper. Specifically, a novel perspective for the ISC detection is proposed that battery voltage will present quite different transient characteristics in the ISC processes and normal operations resulting from different battery load inductances. On this basis, an on-board signal processing based detection method is proposed with an idea of extracting and converting the AlCu ISC signals into a steady digital signal by an ingeniously designed circuit so that the occurrence of the AlCu ISC can be continuously indicated. Verification results show the proposed method has outstanding reliability and detection performance, and is promising to be implemented in practice.