Evaluating the Inherent Safety of Li-ion Batteries in Portable Electronics Used in Underground Mine Environments

We propose to develop an operational database and functional understanding of the inherent safety of commercial secondary Li-ion batteries used in portable communications, tracking devices, cap lamps and AMS equipment operating in mine environments. Many safety issues with current Li-ion batteries are derived from thermal runaway and the intrinsic flammability of organic solvents, which can result in explosion and venting of hot gases. In mining environments where fine coal dust and methane gas can act as potential ignition sources, thermal runaway of Li-ion batteries can further jeopardize the safety of miners. To this end, we will evaluate the potential ignition hazards of commercial Li-ion batteries subjected to mechanical (crush) and overcharge/ over-discharge abuse testing operating in a mine environment (methane/air gas mixture). A pragmatic study of the potential ignition hazard of commercially available cells will be evaluated as a function of cathode and anode chemistry, electrolyte solvent and state-of-charge (SOC) under crush testing and over-charge/over-discharge abuse conditions in a mixture of 6.5% CH4/air. Data generated in this study will be used to evaluate risk potential for ignition hazards, develop recommendations for selecting commercial battery chemistries and establish safe maintenance and operating protocols for devices using Li-ion batteries.