Military applications of reserve batteries

Reserve batteries are batteries which do not give power until activated. They have a long storage life and high power capabilities which makes them useful for numerous military applications. Designs of reserve batteries include those based on movement of electrolyte (sea water, energizers and reserve silver-zinc or lithium-thionyl chloride) and thermal batteries, which are high-temperature batteries activated by heating using an internal pyrotechnic. The increasing shelf-life of lithium primary batteries and the higher energy density of lithium reserve (particularly thionyl chloride) batteries is allowing these to replace aqueous electrolyte reserve batteries in some applications. Increased energy density of recent thermal batteries makes them more attractive for applications which have previously used other reserve batteries.