Study of DC Arc Flash Phenomenon from 1000 V Lithium Ion Battery Systems

Many civilian and defense applications are either considering or actively incorporating 1000 V electrochemical energy sources into their power systems for a multitude of uses. It is well known that lithium-ion batteries can introduce significant safety challenges, but the risk is most often worth the reward. In addition to the shock hazard that comes with high operational voltages, the potential danger to workers from arc flash hazard: intense heat, bright (blinding) light, and loud (deafening) sound, also exists and it is not well documented from dc sources. As batteries become more attractive for use across industry, the risks posed by these sources drives a need to study the arc flash phenomena produced at application relevant potentials. Consequently, the Electric Power Research Institute (EPRI) and University of Texas at Arlington (UTA) have performed 91 arc flash experiments with battery sources at voltages at roughly 1000 Vdc. Data collected from these experiments is the first comprehensive experimental analysis of dc arc flash phenomena from 1000 V lithium-ion battery systems, revealing previously unreported non-thermal hazards and overestimations from models typically employed. Two lithium-ion chemistries have been studied, Lithium Iron Phosphate (LFP) and Lithium Titanate (LTO). LFP modules studied previously at 540 V produced incident energies as high as 6.12 cal/cm² from an arc lasting 2.39 s with a gap distance of 0.25 in. At 908 V, the same LFPs exhibited upwards of 4.48 cal/cm² from a 0.5 in gap distance tests that had to be manually cutoff. LTOs at 730 V produced 2.16 cal/cm² for an arc lasting 0.88 s at a gap distance of 0.5 in. The light and sound intensity studied in some tests indicates the necessity for workers to use hearing and vision precautions. Models developed through this research and two relevant models from literature have been used to evaluate overestimations and their effectiveness to predict the incident energy for arc flash events sourced from lithium-ion batteries.