Bipolar Silver Zinc Technology for Primary Battery Applications 929461
The demand for increased performance from batteries in missiles, space applications and torpedo propulsion has generated extensive battery development over the years. Dramatic improvements in the specific energy capability of the Silver Zinc System can be expected only through the development of new materials, novel approaches and/or new concepts in the design of the Silver Zinc batteries. One concept that Yardney is currently re-evaluating is bipolar construction.
The major incentive for the use of bipolar cells in a pile configuration is the elimination of intercell connectors, other heavy current carrying structural elements and some of the cell containment features. This allows for substantial weight and size reduction, while increasing the specific power/energy density of the battery. Much of this work was originally developed by Yardney in the late 1960's to early 1970's. With new materials and processes available such as fast wetting, thin separator material, Yardney has revived this technology in support of a reserve, primary battery application. The monoblock configuration tested on this program reflects the utilization of new materials as well as new approaches to bipolar design.
This paper presents the results of four ampere hour primary cells, that have been developed and tested in groups of twenty cell monoblocks and 100 cell batteries. Discharges up to 200 amperes (at 1.8 amperes/cm2 (surface area) has produced very stable voltages and full capacity yield which are typical of a monopolar design. In addition, discharges at nominal current densities of 0.16 amperes/cm2 have yielded excellent load voltages with flat discharge curves. Based on analysis of program results Yardney has concluded that continued development of the bipolar design is warranted.