LITHIUM ION BATTERY AND ELECTRODE WOUND BODY FOR LITHIUM ION BATTERY

In a lithium ion battery, including: a battery case; and a wound electrode body formed by attaching an unwinding prevention tape to a circumference of a wound electrode structure which is formed by winding a laminate of a tape-form negative electrode and a tape-form positive electrode together with a tape-form separator interposed therebetween, and a non-aqueous electrolytic solution, sealed up together within the battery case; the unwinding prevention tape is formed of a composite material of a vinylidene fluoride resin and an aromatic polyester resin. As a result, it is possible to provide a lithium ion battery which can stably prevent the unwinding of the wound electrode structure and a decrease of power even under a high-temperature service condition as encountered in a large-power use, and also such a wound electrode body for the lithium ion battery.