Fabrication of High Burn Rate Fuse Strip for Thermal Battery

Abstract

Thermal batteries are widely used in various military applications such as missiles and torpedoes due to high power output, long shelf-life, and reliability. In order to react quickly to an enemy, quick activation time of the thermal battery is required. In the process of activation, fuse strip transfers heat energy to the heat source of each layer. Therefore, to achieve short activation time, fuse strip with high burn rate is highly needed. However, although there are lots of variables affecting burning rate of fuse strips, such as a combination of fuel and oxidizers, additives and particle size, it's not well-studied yet.In this study, we fabricated high burn rate fuse strips by applying additives and new oxidizer. Usually, to fabricate fuse strip, Zr and BaCrO4 slurry is deposited onto supporting ceramic paper and then dried. In order to improve burn rate, we additionally applied HDC-M10, NH4HCO3 and PbO into the Zr/BaCrO4 slurry. The retention agent HDC-M10 makes the dispersion solution stable, making the structure of fuse strip uniform. And the blowing agent NH4HCO3 controls the distance between the particle that makes optimal heat transfer path between the Zr and BaCrO4 particles. Also, PbO was chose as the best additional oxidizer among other several oxidizers which has appropriate reactivity, burn rate and heat calories. The mixed slurry was placed on a sheet former and then made into hollow cylindrical shape. The burning rate was then measured by self-made burning rate measurement equipment. As a result, we observed 10 times improved burn rate than previous studies. In addition, the fuse strip was applied to the thermal battery and its test result is also presented in this study.