Use of NanoFoil as a New Heat Source in Thermal Batteries

In order to realize the great potentials of nano-layered bimetallic foils as a new source of heat for thermal batteries, the properties of NanoFoil by Reactive NanoTechnologies were extensively studied and discussed, including the speed of flame front propagation both in absolute terms and in relation to that in the heat paper, the ease with which the NanoFoil would catch fire edgewise from the heat paper, the heat of reaction, the electrical resistance, the rate of temperature rise due to the NanoFoil relative to that due to the pyrotechnic material, the effects of buffer discs in limiting the peak temperature generated by a stack of NanoFoil discs, the peak temperature as a function of both the numbers of NanoFoil and buffer discs, and the flow behavior of the NanoFoil at the time of initiation and under pressure. For actual application of these foils to thermal batteries, an Al-Ni NanoFoil was used as the sole source of heat to build a 4-cell and several 2-cell thermal batteries. These batteries were discharged at different current loads and monitored for their electrical and thermal performances. Their internal resistance was also determined from a pulse train in the discharge current and the voltage response in their voltage-time curves. These results were carefully compared and thoroughly discussed for gaining important insights. Most importantly, the results have shown that use of NanoFoil as a new source of heat in thermal batteries is feasible and advantageous.