NOVELTY - Large-capacity power lithium-ion battery comprises positive electrode; film of gel polymer electrolyte; and negative electrode. The negative electrode is isolated with the positive electrode by the film of the gel polymer electrolyte. The active material of the negative electrode is modified lithium titanate. The active material of positive electrode is ternary material, lithium permanganate, and/or lithium iron phosphate. The film of gel polymer electrolyte is formed by mixing and drying lithium salt, solution of organic solvent, and conductive polymer solution.    USE - Large-capacity power lithium-ion battery used as power source e.g. for hybrid electric vehicles and electric automobile.    ADVANTAGE - The large-capacity power lithium-ion battery is environment friendly and easy for large-scale production; and has good high rate discharge performance and heat dissipation, simple preparation, no environment pollution, no leakage, long storage life, and wide usage temperature range.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of large-capacity power lithium-ion battery including:    (A) dissolving 75-98 wt.% modified lithium titanate, 1-15 wt.% conductive agent, and 1-10 wt.% binder in solvent to form a sizing agent of negative electrode; using aluminum foil having a thickness of 9-13 mu m as current collector; coating the sizing agent of the negative electrode to the positive and negative sides; drying the sizing agent to form a pole piece; and laminating and shearing the pole piece to form negative electrode;    (B) dissolving 80-98 wt.% active material of positive electrode, 1-10 wt.% conductive agent, and 1-10 wt.% binder in solvent to form sizing agent of positive electrode; using aluminum foil having a thickness of 15-20 mu m as current collector; coating the sizing agent of positive electrode to the positive and negative sides; drying the sizing agent to form a pole piece; and laminating and shearing the pole piece to form positive electrode;    (C) dissolving lithium in organic solvent to form potassium salt solution; mixing the potassium salt solution and conductive polymer solution; coating the mixture to surface of polyethylene porous film or electrode; and drying the mixture to obtain the film of gel polymer electrolyte;    (D) obtaining semi-finished products of power lithium battery by piling up, enveloping, welding the tabs, and encapsulation of negative electrode, positive electrode, and film of gel polymer electrolyte successively; and    (E) forming, capacity grading, and detecting to obtain the product.