Plastic cased lithium batteries: the challenge to achieve hermiticity and safety

The achievement of sealing and hermiticity for the Ultralife lithium manganese dioxide battery is explained, beginning with the design of the battery case and interconnect cover. Also discussed are the selection of materials and the manufacturing process. Ultrasonic welding of the battery assembly is described with particular attention to materials, design of case parts, welding process control, and testing for hermaticity. The permeation of the battery case by water and electrolyte solvents is also addressed. An ultrasafe safety separator shutdown mechanism is described. The development of this safety feature is followed from selection of materials, through manufacturing, process control, and testing