The EMPF recently initiated a Thermal Battery Development Project in conjunction with Alliant Techsystems (ATK). This U.S. Navy ManTech program formed in response to military demand for batteries with longer shelf lives. The program goals are to demonstrate thermal battery manufacturability and facilitate the entry of a new company into the thermal battery market. The focus of this plan is to use the DSU-33 Proximity Sensor’s thermal battery (Figures 1-1 and 1-2) as an initial test platform. The DSU-33 has been identified as having an immediate need and will benefit from having an alternate U.S.-based supplier. Additionally, the battery designed for the DSU-33 can be implemented into other applications because of common size and power requirements.

The objectives of the Thermal Battery Development project include:

1. Identification and documentation of manufacturing processes that pose challenges to new thermal batterysuppliers
2. Identification and documentation of a baseline test process to use as a reference for the interested new market entrants
3. Demonstration of thermal battery prototypes that meet mechanical, electrical, and environmental requirements for the targeted application

Expected benefits include:

1. An alternative U.S.-based source
2. Increased competition to drive productivity and cost improvements
3. Increased domestic production capacity to address DoD needs
4. Access to basic thermal battery technology information to assist market entrance of additional DoD suppliers

Thermal batteries belong to the reserve battery class – single-use batteries with over ten years of shelf life. Other important reserve battery characteristics include hermetic seals, inert storage state, and rapid activation. Thermal batteries perform well in hot and cold environments and are capable of withstanding adverse storage conditions without performance degradation. The battery’s electrolyte is a solid at room temperature. Activation involves pyrotechnically heating the battery to operating temperature (400ºC to 600ºC). At operating temperature, the electrolyte melts and activates the electrochemistry. After use, the temperature falls below 400ºC, and the battery becomes inactive. Thus, used batteries can be stored safely prior to disposal.

Thermal batteries are used for high power applications requiring runtimes from a few seconds to a few hours. These batteries are almost exclusively used by the military and are typically used to provide power for sonobuoys, mines, missiles, guided artillery, countermeasure devices, and guidance systems. In contrast to batteries used in commercial applications, thermal battery production volumes are low.

Historically, thermal batteries have been notoriously difficult to manufacture in large quantities. Processes such as powder formulation, electrode pellet formation, and cell stack assembly have proven difficult to implement in a cost effective manner. Production quantities remain low, and occasional yield issues further exacerbate the supply problem. The fact that there is no commercial demand for thermal batteries further reduces the market attractiveness to new suppliers. Low volume orders discourage new entries into the market, reducing competition and limiting industrial ramp-up capability for Navy and DoD needs; therefore, current domestic manufacturing infrastructure does not meet the Navy’s cost and volume requirements. This limits the number of thermal battery powered weapons systems that can be purchased and deployed by the Navy.

This U.S. Navy ManTech project was initiated in order to expand the thermal battery industrial supplier base. ATK was chosen as an initial participant because of the expertise found at the ATK Power Sources Center (PSC) and the ATK Thiokol division’s expertise in material properties and powder processing techniques. Experience in thermal insulation and heat management of rocket motors will be transferred to optimizing the thermal battery’s heat management and ignition designs. Experience manufacturing lithium batteries for military and aerospace applications at high volumes will assist the design of the thermal battery production line.

The EMPF’s Thermal Battery Development Project will take the thermal battery prototype from hand fabrication to a production-ready battery. This project is the next step to design, develop, and test a production battery. The process includes defining the standards, tooling, and equipment requirements for a future high-volume production line. An expansion of the industrial base would reduce the current gap between capacity and demand, driven by the needs of the Navy’s thermal battery powered systems.

The Thermal Battery Development Project is an example of how the EMPF leverages its electronics manufacturing experience and its partnerships with industry to dynamically service DoD needs. Specifically, this program showcases the EMPF role in the identification and solution of manufacturing technology issues affecting batteries and power electronics systems used in DoD applications. Other battery and power system projects the EMPF has conducted include development of the SDV battery, the PRC-112 survival radio battery pack, the MOFA reserve battery, and the Integrated Power System (IPS).