The invention provides a method for manufacturing a high-energy-density pouch battery, which includes the following steps: Step 1: Wrap the bottom of the lithium battery core with an auxiliary electrode of aluminum foil, and use a separator to isolate and insulate the battery core and the auxiliary electrode of the aluminum foil , to obtain a pouch battery after assembly; step 2: inject electrolyte 1 into the pouch battery obtained in step 1, and use the aluminum foil auxiliary electrode for pre-charging after sealing; step 3: take out the aluminum foil auxiliary electrode after pre-charging, and remove free Electrolyte 1 is injected into electrolyte 2, and after post-treatment, a high-energy-density pouch battery is obtained. In the present invention, an aluminum foil auxiliary electrode is preset at the bottom of the lithium ion battery core, and through the synergistic effect of the aluminum foil auxiliary electrode and the electrolyte solution 1 containing additives, the pre-embedded lithium on the negative electrode of the lithium ion battery is realized during the small current precharging process, solving the problem of Or improve the problem of low charging and discharging efficiency of lithium-ion batteries for the first time, thereby increasing the capacity and energy density of lithium-ion batteries.