2025 International Conference on Equipment Intelligent Operation and Maintenance (ICEIOM2025)

With the increasing demand for electric vehicles and large-scale energy storage systems, lithium-ion batteries (LIBs) face critical safety challenges, particularly thermal runaway. This study proposes a non-invasive method to calculate the equivalent short circuit resistance of lithium iron phosphate (LFP) pouch batteries during thermal abuse using signal easy to access, such as open circuit voltage (OCV). The method estimates energy depletion from the OCV curve and calculates equivalent short circuit current and resistance. Validation is performed through constant current discharge tests, which can simulate OCV profiles during thermal abuse by adjusting density of constant current discharging, and the density of discharging current can represent the value of equivalent short circuit current. Experimental results show that short circuit resistance decreases significantly as temperature increases, indicating more severe faults. The proposed method offers a practical tool for quantifying short circuit severity and contributes to improving battery safety analysis.

lithium-ion battery,thermal runaway,short circuit resistance