Flexible packaging for polymer electrolytic cell and method of forming same

A method of packaging a rectangular electrolytic battery, comprising the steps of forming a sleeve from a flat, rectangular sheet of a laminate material by overlapping and joining opposite edges of the sheet; inserting a rectangular battery into one end of the sleeve, the battery having two electronic contacting leads extending from one side thereof and the battery being positioned within the sleeve wherein a portion of the leads is within the sleeve and a portion of the leads is outside said sleeve; joining the ends of the sleeve to form a seal along each end thereof, hermetically sealing the interior of the sleeve, one end of the sleeve forming a seal about the leads and the other end of the sleeve sealed adjacent the battery.