A manufacturer of thermal batteries, used in Missile Systems, completed a new battery design and was concerned about stress to its hermetic glass seals in its D38999 style header. This header acts as a connector/battery cover and protects the battery’s critical components. Historically, exotic titanium sealing glass material has been used, but given the higher voltage needs of this new battery, the increased stress on the header forced the customer to pursue glass seal alternatives to meet its hermeticity requirements.
Thermal batteries provide a high burst of power for a short period of time with power output ranges from a few watts to several kilowatts. The batteries are designed to be rugged and have a long shelf life in storage, making them ideal for missile system applications. Each battery has a hermetically sealed header to protect the internal components of the thermal battery. During the manufacturing process of the battery, anodes, cathodes, electrolytes and a heating mass are pressed together to create a series of cells or battery stack. The actual number of cells in the battery stack varies depending on the required voltage level of the battery. As batteries require higher voltage levels, such as with the increasing power requirements of missile systems, more cells are added to the stack, which puts additional pressure on the header. Historically, thermal battery headers have utilized either a stainless steel, titanium, or Inconel® material “housing” with Alloy 52 pin/contact material. The new battery design required higher power and would use additional power pins within the design to help meet this requirement.
Winchester Interconnect proposed a solution that maintained the titanium header and standard alloy pin material design, but optimized performance by utilizing a standard compression glass seal instead of an exotic titanium sealing glass solution. Winchester was able to offer the standard glass seal by creating a two-piece insert construction that utilizes dissimilar metals. Specifically, Winchester used a bi-metal, explosion bonded, Stainless Steel/Titanium insert that was laser welded into the center of the connector body. This unique construction allows for significant performance improvements including:
The Winchester Interconnect Explosion Bonded Thermal Battery Header solution provides: