▎ 摘　　要

NOVELTY - Modified polyester film, comprises 94-99.2 wt.% polyester, 0.5-3 wt.% bridging agent and 0.3-3 wt.% auxiliary agent; where the bridging agent includes diethylene glycol, polyethylene glycol, diglycerol, triglycerol, tetra polyglycerols, penta polyglycerols, hexad polyglycerols, hepta polyglycerols, octaglycerols, nono polyglycerols and/or decapolyglycerols. USE - The modified polyester film is useful in composite current collector and electrode sheet od battery (claimed), which is used in electric automobile and mobile electronic device. ADVANTAGE - The modified polyester film effectively improves the molecular weight and crosslinking degree of the polyester, and improves the mechanical property of the composite current collector. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: preparation method of modified polyester film, comprising preparing a polyester chip, making the polyester chip into a film and performing electron beam irradiation treatment to obtain a modified polyester film. a composite current collector, comprising a modified polyester film and a metal layer on at least one side of the modified polyester film. an electrode sheet, comprising composite current collector, and an active material layer attached to at least one surface of the composite current collector. a battery, comprising the electrode sheet; and an electric device, comprising the battery.