Investigation of the Dielectric Breakdown Strength of Vented Li-Ion Electrolyte

The future fleet of the U.S. Navy vessels may be deployed with a number of high-power electrical loads that operate transiently. The transient nature of the loads will impart high stress on the traditional shipboard power system, possibly pushing it outside of the acceptable power quality standards. To restore power quality and increase system reliability, it is being proposed that electrochemical energy storage systems can be utilized to augment the existing generation systems. Lithium-ion batteries are of extreme interest due to their high combined power and energy density. The proposed energy storage systems will store a great deal of energy and could be designed with open-circuit potentials as high as 1 kV. Since size and weight aboard the vessel are limited, the batteries need to be designed as compact as possible. In the event of a battery failure, in which one or more cells are compromised, organic electrolyte may be vented within the air dielectric separating points of higher and lower potentials. How the vented electrolyte impacts the dielectric strength of the surrounding environment is of concern, especially given the battery's high operational voltage, its compact construction, and the high energy it stores. The study documented here is aimed at studying the dielectric strength of the vented electrolyte from a lithium-iron-phosphate battery when exposed to potentials representative of a future shipboard energy storage system.