43 preferred values are about 40 or p 60 these maxima correspond to critical values of the relative proportions of solvent and of co solvent and to produce usable primary cells in accordance with the invention the proportions should be chosen from between the two critical values discharged at 70 u00b0 c to simulate a long storage period these cells give even better results than during discharge at ambient temperature the lithium tetrachloroaluminate of the electrolyte could be replaced by lithium hexachloroantimoniate likewise analogous results from the point of view of proportions of solvent and of co solvent are obtained by replacing thionyl chloride by sulphuryl chloride let us now refer to the discharge curves of fig4 two series of primary cells in accordance with the invention are installed the only difference being the composition of the electrolyte series a corresponds to the type described hereinabove the electrolyte is made of 60 thionyl chloride 36 phosphoryl chloride and 4 lithium tetrachloro aluminate all the percentages are given by volume the concentration of the solute corresponds approximately to 0 5 moles per liter in series b the electrolyte is made of 58 7 thionyl chloride 33 3 benzoyl chloride and 8 lithium tetrachloroaluminate about 1m these two series of primary cells were discharged through a resistance of 1000 ohms at ambient temperature discharge curves a and b are shown in fig4 where the voltages v are plotted along the y axis and.