A new process for the preparation of lithium-polymer batteries with crosslinked gel-polymer electrolyte will be introduced. The new process employs a thermal crosslinking method rather than cell lamination, and is termed ”lithium ion type polymer battery (ITPB)”. This thermal crosslinking process has many advantages over the standard lamination method, such as fusing the polymer into the electrodes and better adhesion between the electrolyte and electrodes. The new method results in improved high-temperature stability and a simpler process, as well as the improved adhesion between electrodes and polymer electrolyte. However, due to crosslinking of the electrolyte, it results in a lower ionic conductivity of 1.3x10-3 S/cm, compared to values as high as 3x10-3 S/cm for un-crosslinked PVdF-HFP.