ROLLED LITHIUM ION SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a rolled lithium ion secondary battery capable of preventing short circuit between positive and negative electrodes even when a twist is generated in a direct tab.

SOLUTION: The lithium ion secondary battery has a bottomed cylindrical battery container. An electrode group is housed in the battery container. The electrode group is formed by rolling a positive electrode plate 17 and a negative electrode plate 18 through a separator 16 so that both electrodes do not contact directly around a shaft. The extended end of a positive electrode direct tab 2 extended from the positive electrode plate 17 is joined to the frame periphery of a positive electrode current collecting ring 4. A porous polyolefin film having a coefficient of static friction of 0.6 or less is used in the separator 16. Even if the positive electrode direct tab 2 twists and contacts with the separator 16, the positive electrode direct tab 2 slides the surface of the separator 16.

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