On the Design of Silver‐Hydrogen Electrochemical Cells

Abstract

With a projected energy density of 70–110 W‐hr/kg and an estimated lifetime in excess of 1000 cycles, silver‐hydrogen cells represent a promising electrochemical energy storage device for specialized applications. A cell design using a rolled stack configuration is especially attractive. A comprehensive computer simulation has been used to optimize the energy density of such a cell. The parameters considered include: cell geometry, electrode and lead dimensions, water generation and consumption, electrolyte movement, heat generation and dissipation, and active material utilization. The results show that balancing of electrolyte transport processes is essential for stable long term operation. Energy density is a strong function of rate, with incomplete silver electrode utilization the main factor. At higher rates no more than three or four layers can be used if the maximum temperature increase on discharge is to be kept below 5°–10°C to avoid electrolyte loss via evaporation/condensation processes. Conversely, use of only one or two layers leads to an unacceptably high penalty in the energy density.