Thermal Analysis of Spirally Wound Li/BCX and Li / SOCl2 Cells

A thermal analysis of Li/BCX and high rate Li/SOCl2 cells is presented. The thermal model developed was used to study the effect of ambient temperature of discharge (0-40°C) on Li/BCX cells discharged at the same rate. The model predictions show that ambient temperature of discharge was critical in thermal management of the cell. For forced convection cooled cells, the model predicted that ambient temperature near room temperature (25°C) was required to achieve the lowest maximum temperature rise in the cell. Inclusion of the effects of reaction products to the model predictions showed that a constant composition assumption may be misleading. Heat transfer through the spiral constituted a smaller fraction of the total heat dissipation from the cell. In a comparison of the thermal performance of high rate Li/SOCl2 cell with Li/BCX cell, the model predicted a higher temperature rise in the Li/SOCl2 cell (assuming the temperature rise behaves linearly with discharge current) if both cells were discharged at the same rate.