Electrolyte Loss Mechanisms of Manually Activated Silver-Zinc Cells and Batteries

摘要

Silver-zinc batteries are used in applications where high energy density and highdischarge rates are required. These batteries do not possess excellent cycle life characteristics, but designs are available that are capable of about a hundred charge-discharge cycles. These batteries are mostly used in the primary mode where they are not required to be recharged. Torpedoes, missiles of many different varieties, and all launch vehicles use silver-zinc batteries in sizes ranging from about one ampere-hour (A-h) to 250 A-h. For the launch vehicle applications discussed herein, batteries are assembled (except for the introduction of electrolyte) and carefully stored until they are called up for use. At that time, electrolyte is added as part of the overall activation process prior to installation on the vehicle. Once the cells are filled, reactions take place that can result in small amounts of electrolyte being expelled from them. There have been several recorded instances where electrolyte expulsion has resulted in the rejection of either that particular battery or the entire production lot of batteries that were felt to have a generic problem. An in flight failure of a battery suggested that the problem resulted from the effects of small amounts of electrolyte forming an ionic conduction path inside the battery box. This report covers the results of examining the causes for the different kinds of problems within a cell that can result in the expulsion of small amounts of electrolyte.