Studies of high reliability long-life Li/SO sub 2 cells

To satisfy the need for a five year battery, a long-term test of Li/SO/sub 2/ cells was initiated. Premature failures were observed and a program was undertaken to identify the cause of these failures. Based on the results of this program, changes in the cell design were made which gave rise to the Sandia modified Li/SO/sub 2/ cell having improved long-life performance. Several lots of modified cells have been manufactured during the past five years. Acceptance testing of incoming cells from each lot has revealed lot-to-lot variation in performance as well as a small proportion of cells with low capacity. A program to develop a nondestructive methodology for identifying cells with low inherent capacity was initiated. Several relevant nondestructive measurement parameters were identified. A decision tree screening technique, based on these parameters, was developed to identify those cells having low capacity.