In the present paper, we are going to investigate the influence of the temperature gradient on the electrical capacity of the Lithium/thionyl chloride cells and the dependence of internal heat generation on the temperature level.Moreover, we will show the influence of temperature gradient between couples on the depth of discharge and so how important is to limit this gradient to prevent discrepancy in couple's voltage and inversion phenomenon.First, we present a theoretical study concerning the influence of temperature on the heat generation of lithium/thionyl chloride couple. This study, which is based on the thermoneutral potential, was carried out using calorimetry measurement. We also display the evolution of discharge tension and current with temperature.Secondly, we present a real evolution of these parameters and that for a lithium battery cooled by an aluminium corset put on a coldplate. A nodal model has been made to simulate battery behaviour and different parameter's evolution for a realistic discharge profile.It follows that pure conduction cooling system is not suitable in the case of high discharge currents in the cell lithium cells. A new cooling concept is proposed to overcome this problem .