Online internal short circuit detection method considering equalization electric quantity for lithium-ion battery pack in electric vehicles

The timely and accurate detection of an internal short circuit (ISC) is critical for improving electric vehicle (EV) safety. Typical ISC detection approaches are based on consistency differences between each cell in a module. However, the indispensable equalizer in a battery management system reduces inconsistency, affecting the accuracy and timeliness of ISC detection. Hence, an online ISC detection method considering equalization electric quantity (EEQ) is proposed. First, the remaining charge capacity and state-of-charge difference approaches are investigated. Next, the negative impact of EEQ on ISC detection is analyzed; thereafter, improved approaches based on EEQ compensation are proposed. Moreover, an ISC routing inspection approach for dormant EVs is proposed. Lastly, the proposed approaches are verified. The main results are as follow: (a) The ISC detection method without EEQ compensation has issues, such as significant errors, undetected ISC, and longer detection periods; our approaches help effectively overcome these issues, while the detection error is maintained below 5%; (b) Supplementing the above approaches, the proposed ISC routing inspection approach can help detect a moderate ISC even for a dormant EV, while further improving timeliness in ISC detection.