On charge conditions for Li-ion and other secondary lithium batteries with solid intercalation electrodes

The simple model of continuous non-porous electrode was found to provide a reasonable theoretical description for the electrochemical process of lithium insertion into a convenient solid electrode, consisting of active material, fine carbon and binder, of the rechargeable lithium batteries with common liquid organic electrolytes. The model uses only one experimental fit parameter–effective diffusion coefficient of inserted Li that can easily be obtained from galvanostatic charge–discharge data. Approximate simple equations were derived to calculate the charge conditions for secondary lithium batteries. It was shown that charging with linearly descending current results in more than 2.5-fold reduction of charging time as compared to the constant current charging at the same charge depth.