Persistent Power Supplies to Extend the Life of Asset Tracking Devices

Betavoltaic (BV) devices are useful in powering devices that require long lifetime, small size, and functionality in extreme environments (e.g., high temperature, high pressure, darkness, hostile areas). The isotope high-energy density also makes these BV devices applicable to small implantable or micro-sensor devices. Electrical power from BV power sources is ideal for long-lived power applications that include space applications or remotely located sensors that are difficult to maintain or resupply with power. Through Phase I, Direct Kinetic Solutions (DKS) had performed an extensive study in the current system that is used by the AirForce and identified limitations, risks and issues with the current power solution that is used for their GPS sensors (WhereTag). Air Force’s WhereTag TFF-3110-00AB GPS tag can only last about 1 year in continuous operation mode because of the current energy storage system setup. The current sensor uses two lithium thionyl chloride (LTC) D cell batteries, one on each side of the GPS PCB. DKS has devised two options, near-term and long-term, to extend the operation time of the GPS tag from 4 to 20 years. The Smart Battery option (near-term) is a LTC battery array operating efficiently using a low-power battery controller to extend operation time to 6 years. The Hybrid Battery option (long-term) is a radioisotope power source (RPS) charging rechargeable batteries with a low-power energy management system, which would extend operation time 20 years. During Phase I, DKS formulated models to simulate the Smart Battery and Hybrid Battery options to improve design. They demonstrated the Smart Battery option in a laboratory setting. They, also, built up mock-ups of the Phase I Smart Battery systems while still using parts of the WhereTag casing. In Phase II, the Hybrid design will be finalized with an emphasis on volume reduction and commercial form factor optimization. DKS will build a D-cell form factor RPS to easily retrofit into existing equipment that leverages this battery size for performance. The prototype will be built and operate under the expected environment of the original WhereTag TFF-3110- 00AB GPS tag and the final product. Finally, for Phase III preparation, the prototype will undergo environmental testing (i.e., MIL-STD-810) specified by the Air Force. If necessary, additional alterations will be performed based on the environmental testing results. For the hybrid option, DKs will further the development of the hybrid battery design with the goal of having a functioning prototype by the end of Phase II. The preparation for Phase III will be similar to the preparation for the smart Battery Option.