Thermal Battery Powder Granulation

Thermal batteries are mission-critical components utilized in virtually every weapon system. Thermal batteries require four types of pellets that comprise the energy-producing portion of the battery. These include: (1) anode pellets, composed of Li(Si) alloy and electrolyte salt, (2) cathode pellets, consisting of either FeS2 or CoS2 and electrolyte salt, (3) separator pellets, consisting of MgO and electrolyte salt and (4) heat pellets containing iron and potassium perchlorate. A pellet is manufactured by compacting its powdered constituents in an automated press. The powder is loaded into a feed shoe, which automatically fills a die cavity. Currently, pellet production is the rate-limiting step in thermal battery manufacture, hence, it is essential to optimize press throughput. The chemical, physical, and mechanical differences between the powders are wildly different. The ultimate material would exhibit excellent flow behavior and compaction behavior. The pharmaceutical industry has done extensive work in this area. One of the methods utilized to improve flow properties and compression characteristics is granulation. This proposed SBIR project focuses on the design challenge to implement a granulation process in order to double pellet production rate. In principle, accomplishing this goal will result in a substantial increase in thermal battery production capability.