Thermal-electrical-linked analysis of a thermal battery powering a guided weapon system

Abstract

Thermal management of a thermal battery is critical to ensure the robust operation of guided weapon systems. The electrical performance of the thermal battery is highly sensitive to changes in battery temperature during operation; the battery resistance increases significantly at low temperatures and the discharge capacity can be significantly reduced at excessively high temperatures. However, the thermal management and electrical performance of thermal batteries have been studied independently without linking them. In this study, a thermal-electrical-linked analysis platform was developed to predict the internal temperature variation and the resulting voltage variation of a thermal battery. The parameters of the Thevenin equivalent circuit model (TECM) as a function of temperature, depth of discharge (DoD), and applied current were obtained from a discharge test conducted on a unit cell. The temperature changes of the electrodes and electrolyte in unit cells were traced during activation and discharge. Based on the simulation temperatures, the thermal stability of the battery was analyzed considering the melting point of each component, and subsequently, the time required for activation and reaching the cut-off voltage was evaluated according to the operating temperature and discharge rate.