A Mathematical Model of a Zn/Br2 Cell on Charge

A mathematical model of a parallel plate electrochemical cell with a separator and a homogeneous bulk reaction is presented. The model is based on the Zn/Br2 redox couple and can be used as an aid for the design of an efficient rechargeable storage battery. It is shown that four independent variables exist for the system at a fixed temperature: the effective separator thickness, the residence time, the channel width, and the potential driving force. Performance criteria of interest for the Zn/Br2 battery are defined. Predictions of performance during the charging process are presented. It is shown that the cell performance improves as the effective thickness of the separator is increased, despite the associated greater cell resistance. It is also shown that a change in the residence time has little effect on cell performance