Measurements of the Fundamental Thermodynamic Parameters of Li/BCX and Li / SOCl2 Cells

The thermodynamic data needed to estimate the heat generation characteristics of Li/BCX and Li/SOCl2 cells were determined using two experimental techniques, equilibrium or reversible cell discharge and measurement of open circuit potential as a function of temperature. The results obtained showed that the reversible cell potential (Er), the temperature dependence of the reversible cell potential (dEr/dT) and thermoneutral potential (Eh) of the BCX cell were respectively, Er,25oc = 3.74 V, dEr/dT = -0.857 ± 0.198 mV/K and Eh= 3.994 ± 0.0603 V. The respective values obtained for the Li/SOCl2 cell were Er,25oc = 3.67 V, dEr/dT = -0.776 ± 0.225 mV/ and Eh = 3.893 ± 0.0776 V. The difference between thermoneutral potential of Li/BCX and Li/SOCl2 cells is attributable to the difference in their electroactive components.