Tape Casting for Development of Thermal Batteries

Abstract

Thermal (thermally activated) batteries are primary batteries which operate at temperatures ranging from 350°C to 650°C. Due to its long shelf life and high power density (up to 8kW kg-1)1, thermal batteries have been used reliably for military applications such as providing back up power for aircraft hydraulics, missiles and even the Galileo probe.2 Currently, thermal batteries are manufactured by a labour intensive pellet pressing method which limits the design and thickness of the batteries. To improve the power density of thermal batteries, tape casting has been examined. Tape casting is a common method of manufacturing commercial secondary lithium-ion batteries. Tape casting enables relatively thin films of battery components to be utilized which minimises the thickness of the battery components and gives the option to alter the design of the battery itself.Despite its many years in operation for important military applications, processing of thermal batteries into functional cast films has not been achieved so far due to the high operational temperatures of thermal batteries which negate the use of standard polymers. To counter this issue, high temperature polymers, inorganic binders and carbon nanotubes have been examined for their use as binders for thermal battery component inks. Their thermal stability was examined using STA and the oxidation of pyrite was analysed through EDS and PXRD. Successful processing of the constituent battery components is hoped to drastically improve the electrochemical performance of the cell and decrease the manufacturing cost of the batteries. R. A. Guidotti, G. L. Scharrer, E. Binasiewicz and F. W. Reinhardt, 1998.R. A. Guidotti and P. Masset, J. Power Sources, 2006, 161, 1443-1449.