Multi-parameter coupling effects on cathode-particle-induced breakdown arc in lithium iron phosphate batteries

Lithium iron phosphate (LiFePO4, LFP) batteries are among the most widely used batteries in energy storage power stations. However, thermal runaway (TR) represents an inherent and extreme failure mode of such batteries. To address the critical issue that particles (e.g., cathode materials) ejected during thermal runaway of lithium iron phosphate batteries in energy storage stations may induce breakdown arcs and ignite flammable battery vent gases, potentially causing fires, this study established an experimental platform to simulate series arc faults. A comprehensive experimental investigation is conducted on the critical conditions for arc induction by lithium iron phosphate cathode powder and multi-parameter coupling mechanisms. Key variables included electrode gap (1–6 mm), particle size (54–500 μm), load resistance (10–20 Ω), and filler shape (normal filling, filling at both ends, and filling in the middle). The results show that LFP particles significantly reduced the critical breakdown voltage (CBV) for arc generation. At a 2 mm electrode gap, critical breakdown voltage dropped to 365 V (only 4 % of that in air). The critical breakdown voltage exhibited positive correlations with electrode gap and load resistance but a negative correlation with particle size. Additionally, filler shape altered electric field distribution, thereby influencing critical breakdown voltage. Results of this study are expected to provide potential theoretical and empirical support for understanding and preventing arc faults in energy storage battery systems.