Three-dimensional thermal modeling of high-temperature primary lithium battery with nickel disulfide cathode

Abstract

Thermal modeling is significant for high-temperature primary lithium batteries (thermal batteries) widely used in military hardware and aerospace equipment. Herein, the three-dimensional (3D) thermal model of a thermal battery with the novel cathode NiS2 and 48 cells is performed to observe the thermal behavior within 500 s from the single cell to the whole battery. From the perspective of unit cell, the Li–B/LiF–LiCl–LiBr/NiS2 cell shows exothermic reaction with the potential temperature coefficient of −0.405 mV K−1, so double heat sources exist in the cell during discharge. From the thermal field of battery stack, the temperature uniformity of the battery stack is the worst at the start of the discharge with a significant temperature gradient (about 90 °C) in the lead-out disks, but then improves with increasing discharge time. According to the thermal balance of the entire battery, the total heat generation is greater than the heat dissipation for the first 325 s and then becomes negative, as the increase in Joule heat is insufficient to offset the decrease in reversible reaction heat with decreasing temperature. This study could provide theoretical guidelines for the thermal design and management of thermal batteries with NiS2 cathodes and other novel materials.