| The thermal and performance characteristics of two electrochemical power sources have been studied. A combination of experiment and theory is used to study the thermal characteristics of Li/BrCl in SOCl{dollar}sb2{dollar} (Li/BCX) cell while the performance of the Zinc/Bromine flow cell is studied theoretically. The thermoneutral potential of a cell is required to predict its heat generation under load. Two experimental methods yielded an effective thermoneutral potential of 4.0 V and 3.84 V respectively for Li/BCX and Li/SOCl{dollar}sb2{dollar} cells. The effective thermoneutral potential for Li/BCX cell suggests a higher heat generation capability in Li/BCX cell relative to Li/SOCl{dollar}sb2{dollar} cell under the same discharge conditions. The heat capacities of the cells are found to be dependent on state of charge--increasing with depth of discharge. DD-Li/BCX has a lower heat capacity (0.154-0.201 cal/kg-K) than the high rate D-Li/SOCl{dollar}sb2{dollar} cell (0.191-0.221 cal/kg-K). A thermal model developed supports the idea that for low internal maximum temperature, ideal ambient discharge temperature for convection cooled cell should be near the room temperature (25{dollar}spcirc{dollar}C). Although the Li/BCX cell generates more heat than the Li/SOCl{dollar}sb2{dollar} cell when discharged at the same rate, the model result suggests that the temperature in the interior of a D-Li/SOCl{dollar}sb2{dollar} cell could be higher than that of a DD-Li/BCX cell due to differences in their reaction products.; A model is presented for a Zinc/Bromine cell in which the effects of an increase or a decrease in the cathode channel width due to zinc removal on discharge and zinc deposition on charge, respectively are considered. The model also includes the effect of an organic Bromine complexing agent (OCA) on the cell performance. Changes in the channel width affect the catholyte velocity, cathode side pressure drop, mass transfer and potential drop in the cell, while the inclusion of the bromine complexing organic phase shows a marked effect on the available bromine in the aqueous phase.; It is shown that during discharge, the slow release of complexed Bromine by the OCA could be detrimental to the cell performance. A simple equation is derived and used to express the relationship between the total Bromine in the organic phase relative to the Bromine in the aqueous phase. |
