The invention relates to the use of a liquid/solid reversible phase change electrolyte to prepare a bipolar lithium-ion battery. Said use is characterized in that said electrolyte contains at least one block copolymer containing at least one polymer segment A, soluble in said electrolyte, and at least one polymer segment B, having a temperature T for solubilization in said electrolyte. The polymer segments A and B are present in sufficient amounts to allow physical gelling of the electrolyte at a temperature greater than or equal to the temperature T.